Hello and welcome to both the worlds of buggies and forums (fora??). The rights to the freestyle design still rest with Dave Smart and he has stopped making them for a while ( how long is anybodies guess). Your best bet is to keep an eye on here and on ebay for a part built ( they come and go every now and then). Prices vary from ( a couple of weeks ago ) less than £100, to around £1000 -£1500 part built.
When pricing one up remember to budget for the IVA test (about £500) if you want to be road legal.