I'm afraid I'm unclear as to why civilianisation of the TT is a bad thing. Fundamentally I doubt any teenager with the desire to tab 35 miles across Dartmoor and the associated training is less likely to join up just because it is sponsored by a private company instead. Who runs the J4 for the event has little impact on the actual experience itself - beyond seeing someone in uniform or goretex at certain points.
Instead the event seems to be a little bit of a self licking lollipop in some ways - the Army needs the ability to run TT because it has to run TT. Standfast the now changed airlift requirement, I'm afraid I see nothing unique or specific about it that requires the allocation of a lot of military personnel, at presumably a not insignificant cost and draw on resources. That the Army has the resources to do this suggests the Army either has too much manpower or it isn't prioritising for military operations - particularly if the best reason for doing this is the notion of using it as an example of practising establishing a camp.
My genuine question is this - notwithstanding the benefits to the participants, what is it that the Army brings to the TT that cannot be done by civilians instead?
Given that I live on/near a couple of the TT routes, I would suggest that Army involvement is required in the following ways:
It goes across at least 2, if not 3 of the live firing ranges in N Dartmoor. Army involvement is required to ensure that the yoof don't manage to bimble into a live range. Not so much a problem on the weekend itself, but mainly when they are up on the moor practising. I randomly took a tuesday afternoon off, and during my run I came across 3 groups navigating their way around. They had gained permission to be where they were (whereas I was skirting the edge of the firing area), and that required Army involvement. Multiply that by the numbers of teams involved and a central POC for training related matters seems a sensible plan.
Whilst there are quite a few Army pax involved, some of them are drawn from Okehampton Camp, thus would be being paid regardless. Same same for quite a few of the TA/OTC elements. Could they do it somewhere other than Okehampton, of course; would it cause a massive nause on the TT training elements, which could potentially result in the cancellation of the entire thing - absolutely.
There is a lot of interaction between the Army and the TT Teams on the Thursday and Friday, as well as over the weekend. Between checking of kit, handing out route cards, manning check points, sorting out if people are fit enough to go on, there is a bit more Army/TTer discussion than you suggested.
Turning this all over to a Civi company is easy to do, and I suspect would result in the cancellation of the TT within a couple of years. As someone who has done a couple of Mountain Marathons (all of which were shorter than the 55 miler!), the per person cost would quickly rise to unaffordable levels. And that would go double for some of the schools from the Devon area for whom the TT is about the only interaction they have with Dartmoor and it's foggy, damp, boggy ways.
As ever, we could civilianise this, but I personally feel that the cost that is incurred is worth it, even if has no tangible output for OC.
Whilst logical, a flaw with this thinking is that it does feed into the hands of those advocating the Civilianisation of Ten Tors and Dartmoor.
Compared to the participants, team leaders, parents and locals, the Army (certainly the Regular component) is often seen as a "johnny come lately", mucking up and interfering with long held procedures and practices.
How do you figure the Army (certainly the Regular component) s seen as johny come lately? Their input starts before the teams are even picked, before the managers are even summoned to Okey for their breif. Which is pretty much all Reg run.
Civilianisation (for Jim30 too) solves nothing. 43X use the ex as their Contingency Bde level exercise as stated. Ergo the whole bde is out, hence lots of people milling about. I know 6 Rifles used to do MATT trg over the weekend too. Take away Wyvern Tor (the Ex name) and you end up with a Bde level ex to run anyway.