Just had a look at current MC Strad market, so here are some stats:
Ignoring the Cat D car at £52K, there are 10 MC Strads for sale on PH and AT. Asking prices go from £55K to £70k, with mileages from 50k at the highest to 14K at the lowest. There are 3 colour choices - white, grey or black. As for locations - 1 in N.Ireland, 1 in Dorset, 1 in Hampshire, 1 in Essex, and all the other 6 are in Yorkshire. 3 have 2 seats, 7 have 4.
The upshot of this is that, as a guide to price, mid/high fifties buys a 2 seat, while low/mid sixties buys a newer 4 seat. So the price spread is narrow, given the 4 year difference in age.
The "average" car has done 25k miles and is £62k.
But still, unfortunately, there are none for sale in blue (or red, yellow, etc.)