Poltimore deer park was licenced by the bishop of Exeter which would therefore predate the gift of the land to John Bampfylde in 1298
Deer would have been fallow deer, introduce to England by the Normans.
Deer parks were usually rounded in shape (to maximise are for minimum fencing) boundaries were usually a ditch on the inside with excavated material thrown outwards topped by a paling fence on top. Made of split timber the tops were kept irregular as deer are less likely to try to jump over it. Sometime parts were kept flat to entice deer from neighbouring areas into the park, it still being difficult to jump back out due to the ditch.
Prior to the Tudors deer parks were predominately used for the production of venison, but this change so that manor houses started to be built inside park which might also have been expanded at this time. This may explain Richard Bamflyde’s decision to build his new house either in or adjacent to the deer park.