Mine was £400 this year with Elephant, that's with an aftermarket exhaust, but I only do about 5000 miles a year with it. I'd expect you'd be looking at no more than £600 - but it depends on your circumstances of course.
Best bet is to shop around, also worth trying MGOC and Peter Best.
Cheers
Justin
Justin - Ex-website button-pusher
2003 MG ZT260 SE No. 144
2018 Mini Cooper Clubman
2010 Suzuki GSX1250FA
197? Triumph 'Mostly'
1975 Montesa Cota 175