Yeah I shopped about for a while and self build is by far the best way to considering some of the prefab ones I've seen dont start any lower than £45k!!
Yep tried it in the garden with the full tarp set up the other evening and by far the most comfortable sleep Ive had, will be going out in thetford at some point and the lake district for a proper outing soon but so far so good! I went for the complete set up including under blanket as I wanted as much comfort and heat retention as possible (knowing what english weather is like) I've taken a lot of hints and tips from varying youtube videos to get what I think now works as a perfect set up (for me)
this is by far the best channel Ive found for useful information
https://www.youtube.com/channel/UCbTDXDBHApa_cvcOx86yJOA