In reply to Landy_Dom:
Lagoons are the best bet. Lion rock only has space for about 5 cars.
I recommend using Union Rock which is just round the corner from Lion on the opposite side of the lake. depends on the size of the group though.
You can get 3 lines on Lion on the right hand side and maybe two on the left (3 at a push) but it's likely there'll be SPA courses going on at either of these two places and many centres in the area use these venues too so it's worth planning for this eventuality.