Coaching

I think Anthony does coach. I am interested in group training ride with different level of handicap. Alternatively, strava analysis may be helpful on local trail. I remember he did the boot camp a few weeks ago.

Yeah and no. I dont REALLY coach - not in the way that @Hawkeye is looking for.
There are a few athletes that i di write programs for, and help with their race programs, and power levels etc - but its not my 'job' and I have just no time to do anything more. Even those athletes that I do help will tell you that sometimes I can be difficult!

Its interesting how little is available to be honest though - the high number of people that ask or inquire is incredible. The lack of knowledge or resource is really something MTBA should be looking at.

In terms of recommendations, and advice for coaches - I would look for someone who is local / can spend time with you face to face before i looked for their success in achieving gold medals. Remote coaching is a VERY difficult thing. It can be done well, but it is so much easier if you are near to, or know, the coach.

The use of Power in the context of MTB racing and training is a rare area of expertise. Even the different demands between XC and Marathon racing require a different approach.

That being said - there are some good books available, and I am always happy to help with direct questions and answers - its only my experience (and that of the riders I help) that I speak from however.
The most important thing in all of this is to build a bank of data. Log everything from every ride. Hard rides, easy rides, flat rides, hilly rides, trainer sessions and group rides...after 3 months you will be able to start to look at the data and take value from it.
Final thing about power - you will need to know your 'baseline' - your fitness - via your threshold power (FTP). The best way to test and ascertain this is a 20min maximal effort. That number - be it 200watts, or 420watts - is the key to pretty much everything.
Hope that helps.

I guess the thing I am looking for is someone to write a program that will help me maximise outcomes within the limitations of my available time, and then tweak it as needed when the inevitable setbacks strike (work, illness etc) so as to give best chances of getting back on target.

Based on a couple of trainer sessions done so far, I'm at about 200w estimated ftp... so lots of room for improvement.

The reason I mention knowledge of seniors requirements specifically is that I know from experience that the usual 3 weeks hard 1 week easy cycle typical for under-40s doesn't allow enough recovery for me in the context of my existing routine.

Whilst I dont want to look like I am shutting you down here - age is certainly not the thing that defines your ability to train or tolerate workload.
I was riding with a 49yr roadie who is still good enough to give pretty much everyone I know a solid kicking...

Here are some things to consider - hopefully they will show why distance coaching, or following a template isnt optimal, and also how much time would go into coaching someone properly...

The 3 week / 1 week cycle is really just an arbitrary level because it fits nicely into a calendar month. Much the same is a 7 day training cycle - it fits into a calendar week.
The ratio of work to rest should be completely specific to an individuals ability to tolerate the given workload - which is typically dictated by their fitness and ability to recover.
At various points in a training cycle you *ought to have* different work:recovery ratios depending on what you are looking to achieve. I often work to a 4 or 5 week on, 3 day off cycle - because I can tolerate that - once fit. I might start the year with 10days on, 4 days easy.
A couple of the riders (both under the age of 30) that I help (who are two of the fastest short track racers in Australia) have been on a 3day on, 1 day complete rest cycle - and despite their ability and physical prowess, this nearly breaks them - because of the enormous intensity for those 3 days.

Workload and Recovery: it changes with you. As should your program. And those changes are very difficult to 'template' - as (like you have identified) life gets in the way - work, family, sickness, motivation, rain, etc - they all play havoc with perfectly planned programs. Again - reasons to find someone who is flexible, who can adapt, and who will listen to you regularly.
Think about how much time that takes to do well - and then relate that to how much people are willing to pay for it - and you will see why there aren't more coaches out there. The math doesn't work. From a personal perspective, I don't charge, but do it as a 'karma' thing. To help people out. I couldn't put a price on it really - even if I had to. If I did, no-one would pay it.

Final thing to consider - and its a point that is often missed - consider the reasons why you like cycling. The group rides, the camaraderie, the social side of things - once you have a program and a power meter all of that changes. Significantly. Even if you ride in a bunch, you will be annoyed if they go too fast, or too slow, or they puncture, or change the planned route mid-ride. It can really change you as a rider - and sometimes not always for the better.
For the riders I help, I try and put in a few (maybe 3 or 4 a month) rides that I call "mental health" rides - no power, no timing, no nothing, other than the sun, the wind and some friends. It keeps you reminded why you love riding.

You definitely need a goal to remind you why you're out there doing hill repeats before the sun comes up

... but I often end up getting that way a bit with training, anyway. By the time the event rolls around I'm looking forward to a few social rides afterwards.

The roadie I use mainly for fitting in training on the way to and from work, or in the hydraulic trainer, so it tends not to be social anyway. A PM on that bike won't impact weekend fun rides.

The PM on the XC bike is just to be able quantify total training load and complete the picture. I never look at the Garmin in singletrack - too busy scanning the trail!

Where do you do these 20min test sessions? Hoping you're not going to say on the trainer

I've done on the trainer and the road. The last one I did was from the Narrabeen bridge and up the Wakehurst Parkway turning left at the first set of lights at Oxford Falls.

Did the 20min test this morning.

It hurt! Especally the pinch at the end. Good workout.

Knows his stuff, I am coached by him and you only have to look at the other athletes and their results to see how good he is. He coaches Jenny Fay, Steele Von Hoff, the Avanti Team etc.