I may be digging myself into a hole here, but how long is the maths paper? And for how many questions?
I have some 50 Qs in 30 minutes, which DS is struggling for time with, then I find one (can't remember where it cam from) which is 30 Qs in 35 mins. Now I open (for the first time) my Letts sets of 4 complete Familiarization tests (it does say copyright NFER on the back), DS says they look like his pre-test papers, but they are 50 Qs in 50 mins.
DS seems to think he did 50 Qs in 30 mins in the pre-test, but his result would indicate this may not be the case - it was either less Qs or more time.