I would say even up here in darkest Yorkshire, that is cheap for that level of work. If you've ever done any of this type of work, you'll understand the difference between a quick rub down, mask up, and respray, (which a few forum members have had done recently for about £1000), versus bare metalling the panels, sorting out minor issues and ensuring they are really straight before spraying. You're talking several times more work.
I suspect it's the olde worlde nature of his premises that keep the costs down. You see prices like £3000 for minor insurance repairs to moderns, that's why so many get written off.
The funny thing is, this sort of work costs basically the same regardless of the vehicle, so for a P6 and other lower value classics, it's a lot of money, yet people regularly pay £10k+ for resprays on high end classics.