Apologies - this turned into a long one
Entirely possible that they'd quote for him as he's an existing customer and sponsored by them. It'd look rather bad if one of your major sponsors decided you weren't a good risk....that and he's got a fleet policy of the size where they probably just look at combined value/mileage rather than each individual car.
Re Admiral, I suspect that's where I'm ending up as I've got a multicar policy with them. I do however have some claims experience with them where, surprise surprise, whilst you don't *have* to use their preferred repairers, you wouldn't get car recovery to anyone you wanted to use.
This ended up backfiring as their preferred repairer* had no idea what to do with a Camaro, couldn't wire it up properly, drained it of fuel (as I presume the fun of having a proper V8 to play with was too much - that and I believe they drove it around in a semi-repaired state to get parts of the repair done) and landed me with a box junction fine whilst attempting to deliver it back (it ended up broken down/out of fuel 200 metres away from my house).
I then had to finish the repair under protest as the car wasn't road legal (rear lights incorrect colour) and claimed it back via the Ombudsman as, despite quoting the precise section of the relevant traffic act and providing before/after pictures, the Admiral complaints department decided to stick with their original judgement. They lost, completely**.
Despite this particular experience I'm still using them. This is for two reasons. Firstly they're basically the only person I can find to quote my Camaro at a reasonable price. Secondly I know that if I end up in a further accident I can refer them back to the original one and they might believe me when I suggest that their preferred people are out of their depth.
Re Admiral generally, on stuff that is more UK normal my experience is much better. MY wife got rear ended whilst commuting nov'21 in our NC MX-5. After a minor delay in getting it to an "authorised repairer" they looked at it and wrote it off. Whilst this wasn't what I wanted, the number they gave us for the write off was more than reasonable (I'd been setting up for a fight and doing my research - it was the hardtop which can add a few grand) and payment was quick. Got a replacement car on the policy for not a fat lot (Harry's £70 not far off) as at that point it was a third car (the write off not having taken place yet), got the money back for the unexpired part of the MX-5s policy automatically and the deductible back fairly quickly as the subrogation came through quickly (this despite it apparently being too low to count as something automatically covered by the recoveries department - I was ready to have a fight on this as it's legally incorrect).
Anyway this is long winded way of saying I've seen both sides of Admiral. I wouldn't use them for something imported/rare, I would use them for something more common/domestic where there is a body of knowledge about repair, or if your car is either going to be totalled or walking wounded (so you're not constrained by their repairers).
*the recovery company managed to loose a major part of the car during recovery. If they hadn't, I'd likely have shortened the repair period by six months and prevented some of the later fun as it included the rear light cluster. Admiral didn't seem to get that they are vicariously liable for the actions of their agents and it didn't matter which of their agents had lost bits - they still have to fix it
**for a small bit of context, I'm an Insurance professional working in claims (mostly in the natural resources sector) so whilst I'm not an expert in motor claims, I still had to study it for my professional qualification and I know contract/tort law to a higher standard as that's what the job is