Posted By: ryanpJust hobby

If its just a hobby then limited/no income to defray cost of the shed renovation and probably a huge investment to insulate / upgrade would be difficult to justify for occasional use. So the original plan to use redundant oil boiler sounds good with radiators rather than UFH with more insulation than the 70mm kingspan, probably 100mm -150mm EPS if you can and think about ventilation, perhaps a small MVHR unit which can be got for about 230 quid doing between 50m3 and 100m3 /hour and make sure the windows (if any) and doors seal properly. IMO good seals are more important than multiple layers of glass.

Plan a good separation between the studio and workshop so that they are independently controlled for temperature.

When you talk to Planning and Building control make sure they understand that it is a hobby workshop and not in any way commercial and that the external appearance won't alter. If it looks like a shed now rather than a stable then call it a shed! ....and follow up any telephone conversation with a confirmation in writing of that call. What you don't want is the conversation to end with them saying "well just to be sure can you put plans in."

<blockquote><cite>Posted By: ryanp</cite>Just hobby</blockquote>

OK so you're pursuing a hobby in a shed that's been in situ for 10 years.
DON'T involve planning or BC, they'll have you spending thousands to keep their bureaucratic machine going.
IMO keep it low key, don't alter the outside apart from normal repairs, paint etc.. Don't go putting in a flue for a WBS that's sure to attract attention.
Insulate and line the inside walls, and secondary glaze the windows, if any, more for noise than thermal. If it was used as a stable then the floor is likely to have a fall, and maybe no DPC. For that I'd close batten the floor maybe include a dpc.?; with treated timber to remove the fall, insulate/infill and then cover with 3/4" or 1" ply ; a wood floor is nicer for a woodworking shop. As I said before, keep the heating electric; radiant panels are easiest to install and timer control is easy.
Think neighbours if you make the project too official someone will suspect your eventual intentions are more than a hobby.
Purely from the woodworking point of view, a double door is nice even if its not used for 99% of the time. When installing the floor think static machine weight, unless already there keep using two phase, albeit a bit limiting, as three phase will definitely attract attention. Sound proofing is MORE important for you than thermal insulation, ( neighbours again ).
Natural daylight is quite important. I don't know your aspirations for your hobby but if you're keen, then more and more machines are likely to follow, routers, saw table, dust extractor etc. etc.; all of which make noise.
Good luck and enjoy your hobby.

folks on GBF are sometimes a bit scathing about non-compliance or non-enforcement of building standards, and I certainly don't recommend it.

But if anyone is considering a 'stealth' development, they could look at the potato crate technique:
https://www.scotsman.com/news-2-15012/demolition-order-served-on-farm-houses-built-behind-tattie-boxes-1-1102619

Yeah, I took it as commercial uses initially, and proceeded on that basis. It is bigger than the 'exempt (from Bldg. Regs) floor plan', but it is not a new building, so I am not sure quite where it stands. I felt pretty sure that if it had been commercial, Bldg Regs would apply.