I started looking a while before my car arrived and was considering something with GT10 --- and all were a reasonable £349 inc all taxes etc and as soon as the 10 plate came out ALL registrations with prefix GT were sold! i didn't bother lookin past the dvla cos they would no doubt be more expensive from whoever bought them.
There are still plenty of plates with GT10 on the DVLA website, I bought mine before March, but there is still plenty of choice.
I got GT10ONE and was thinking of getting GT10TWO, if I could afford 2 GTIs, which of course I cant, but it is still for sale.