It looks like it can be part of the 45 hours.
Take a look at
http://www.caa.co.uk/docs/175/srg_fcl_gid21.pdf
You must have completed 45 hours of flight time to
apply for a JAR-FCL PPL(A). The skills test cannot be taken until you've completed the required training and passed the theoretical exams (see part 4), but the required training only adds up to 35 hours (25 P.u/t, 10 P1 of which 5 nav - see part 2). As far as I can tell the other 10 hours can be anything, potentially including the skills test.