Dont know of any in the forest but there is a few arround the Kings Sombourne area and it is not to far to get up to Salisbury plain. Last time I went most were over grown and scratchy. Best to get some ordnance survey maps of area . I use the explorer range of maps 1 : 25000 scale, numbers 130 and 131. There is a shop on Shirley high street with a good range cant remember the shops name though.