I agree with Tim on this. Also check out their 1.2 rating on Trustpilot
https://uk.trustpilot.com/review/www.british-car-auctions.com
Aside that cars go to auction for a reason and it's rarely positive. The best go to the main dealers, then usually trade only at auction, which BCA is. No proper warranty, no viewing, online only, significant buyer fees to pay.
Caveat emptor to any member of the public brave enough to consider buying expensive cars from BCA