This flight actually went well and i'd guess I used about 1/3-1/2 of R31 including ground roll. Regarding Ghengis' figures:
Landing
Runway 31, length 425m, but no landing extension.
Cessna 152, standard landing distance 366m x 1.1 grass factor x 1.43 safety factor = 575m.
Is the safety factor not just for public transport ops? I don't recall that in the PPL and it would preclude going to a lot of smaller airfields.