PSA8 Pokemon base set of standard holo 1-16, UK prices?

I am being offered 1-16, full set of holos from the 1999 base set, standard cards for £1,750 they are all PSA 8.

I've tried to compare online, but wow, is it difficult. Anyone a little more experienced than myself guess as to whether this is a fair offer?

I looked at complete sets and with the other cards ungraded they were £2,500+ and then a full set of graded PSA 8 was £4,500. I've looked at individual cards and priced them up via some of the card websites but then checked their prices vs current eBay and they were off quite sigifniciantly.