Hi @jsteele & welcome!
I'm based in Aberdeen (there are a few of us up here!) & can confirm the Chester trip will be fine (I have an S70). I've done Aberdeen-South Wales several times in summer & winter (passing Chester on the way) and it's one of the better-served UK routes in terms of Superchargers, in fact you have the luxury of choosing between different stops on the M74/M6 rather than doing fixed hops. Warrington is the only 2-bay Supercharger on the route and is the only one to avoid if you don't want to risk queuing. That said, last week I queued at Gretna (4 bays) for the first time ever but this could have been avoided by using Tebay (8 bays) & Abington (6) (it was also lunctime on a Saturday so probably peak usage time).
I've found abetterrouteplanner charge times/energy usage forecasts at different temperatures are pretty accurate. Cross-check trip times with something like Google maps though as ABRP doesn't seem to account for typical traffic delays. The good news is that if there are hold-ups you tend to use less energy (travelling slower) so charge times go down a bit.
The enforced charging breaks are actually preferred by my family. Autopilot (I have the first version) is also very good for motorway driving.
As for service support, so far so good for me (coming up to 3 years next month). The Edinburgh service centre has an excellent reputation and they support customers all over Scotland including the NW highlands. Anything warranty-related and they will send a driver up to collect the car and drop off a loan vehicle (if your car can't be driven it will be taken on a trailer which also brings the loaner). This has happened twice to me, both times the car was driveable but not for long distances. I've had one service to date and they also did a free collect and deliver for that too. I'm not 100% sure if they offer a mobile technician yet (will make some enquiries).
Obviously if you're stuck at the roadside and need to get going they can only do so much from Edinburgh so normal AA/RAC is recommended. But that also applies if you live next door to a service centre as they are only open during office hours (the tyre replacement service is a nice bonus but not one to absolutely rely on). I should add that phone support is 24/7 as you'd expect.
This is the first car I've owned with a remote service centre and my experience has been overwhelmingly positive (it was a concern at first but has proved much better than hanging around the coffee machine at Arnold Clark!).
Any other questions just shout. Oh and if the man maths works out make sure you get a referral code from an existing owner (plenty to choose from on here ).
Thanks for the answer and so much info! The service you've had from Tesla sounds fantastic, very reassuring to hear. I guess Tesla have no obligation to provide quite this level of support? I suppose there is a risk the level of service could drop in the near future, but hopefully not!
I'm still working on the man maths . The total cost of ownership at 10k miles/yr is working out a good 50% higher than the sensible family cars I started looking at (VW TIguan, etc) but having test driven the Tesla I'm just not interested in anything else now!
It seems financing a nearly new car with a Tesla PCP is much more straightforward and with lower interest rates compared to a used one, so I'm thinking more in that direction now. If we trade in our current car as a deposit then the PCP monthly payments work out quite reasonable at <£500... makes it very very tempting....