There's a couple of folks here from oop North - I'm not as you can see, so I can't recommend an indie up that way. I would certainly suggest that it's worth driving down either to Phil Crouch at CPC in Amersham (Bucks) or Jags at BM Sport in Bexley (Kent) if you can't find one.
My F10 is, as far as I'm advised, the only one in Europe with a factory tow bar but I can tell you it copes with a large trailer with two bikes, fuel cans, wheels etc happily. It also copes with that same trailer with well over a ton and a half of rubble on it (yes, they did put me on the weighbridge at the dump and wagged their fingers at me)...
Touch wood I've had nothing major go wrong in 45,000 miles and 3 1/2 years, though there are a couple of niggles to get sorted - mainly around the idrive which will be replaced under warranty - and running costs are very reasonable for a big powerful car. It does...OK on fuel. Tyres last about 20,000 miles and I put winters on for the, um, winter. It needs them. Still on the same brake pads, which is a surprise.
Warranty is certainly worth it if you don't know the history of the car. And probably is if you do, to be honest. Just read the small print to see what they don't cover.
Do hold out for an LCI car - post 2014 - because the satnav and idrive are better. If you can get the LED lights they are astounding and worth every penny. Split/fold rear seat is great for practicality and doesn't ruin comfort.
Whatever you do, you'll love it. It is a truly fantastic car.
PS How's the Alfa?
PPS I'm staggered that running a Guilia QV you can possibly worry about maintenance costs on a BMW
(I've had five...)
2015 F10 M5 in Imperial Blue
2001 E39 M5 in LMB. Stoptech BBK, braided lines, Intravee and Alpine DAB
2000 E39 M5 in Silverstone - Died at 218,000 miles (accident
2007 Full factory SBK CBR-1000RR for...going really
2018 S1000RR Sport for going even faster than the Honda...but with mirrors and heated grips