Darn it I need a new shed

I inherited a shed on my new plot but after looking at it I have come to the painful realistic notion it needs replacing.. Has anyone used a reasonable price supplier who will also build it I site? I'm in bristol

Once you know how & if you can move it - I used these to get my shed (pic on my diary)
http://www.elbecgardenbuildings.co.uk/index.aspx

They charge £150 to construct the shed - though I don't know if that is reasonable or not, never having done this before. I chose to put it up myself, but it's taken me ages to get as far as I have...