Tornup
I think I'm slightly ahead of you in this process.
Nice as DIY would be, I wouldn't have the time to do it plus I have the contents of the old shed spread between the in laws and friends. Consequently a pre built job is the quickest option.
I've ordered a 4.8m X 3.6m workshop from
Passmores. They were recommended to me and have been very helpful thus far. Shed is due in two weeks so can't comment on quality but they were a £1000 cheaper than the cheapest local firm!
I've had a mate round to lay a 4.6m X 5m X 100mm concrete slab which he finished yesterday. He used a mixer but he, with a little assistance from me, did everything by hand.
We've had an awful lot of groundwork prep to do and I'm still digging a bank out for 3m of gabion baskets.
I'll put 25mm celotex board in as insulation and will probably OSB line the interior. I'll also ask the installers if I can insulate the base with celotex board when they arrive.
I've had an old shed base outside under a lean to arrangement for a number of years and it's in surprisingly good condition. It was resting on breeze blocks on a shingle mix and it makes me wonder whether I need to worry about a dpc.
Pics to follow