These two are similar but can be told apart by the combination of bristles.

P. ruifiventris has one pair of pre-sutural acrostichal bristles and 3 posterior setae on the mid tibia. You can see both of these clearly on your image. (P. subventa has 2 +2)

Thanks very much for the help, David, I'll make a record of this one now I know what I should call it!