Just a suggestion but there are huge quantities of brambles* on the path between Gilbertstoun and Newcraighall. Easy ride on the NCN from Edinburgh. Afterwards a short diversion along pavement (or road) to Newhailes (NTS) for refreshments (11-5 open Sundays).
Note - all the brambles are at the newcraighall end. The bushes at the Gilbertstoun end have none.
I got 2kg in less than half an hour.