Making it warm

[Penellype]

I would be wary of using a heater too near plastic panels as they could melt. Aluminium will be fine as will glass.

Hotbeds do work, although you will need horse muck containing straw for best results. Wood shavings is a popular bedding nowadyas but it doesn't get nearly as hot as straw. I followed the instructions in this video to make mine: How to make a hotbed | Learn How To Garden. I used shavings muck, and managed to grow courgettes and beans slightly earlier than I could outside (couple of weeks).

[shewhoguards]

HiSWG and welcome to the Grapevine
Any GH, new or old, needs to be fastened down. What is it on, soil/paving?

About half and half (and not very flat ground either). The people we bought the house from seemed to spend a lot of money buying things for the garden that they then never used, it's a bit weird. When we first started cutting the garden back it was so overgrown that we found a big roofed bench and a wheelbarrow that were so lost in the bushes we didn't even know they were there!

[Potstubsdustbins]

#8 The slide in panels in that GH work well I have them in mine, but you will need to apply silicone as you assemble.

The only downside as far as I can see is the curved roof takes away the height around the sides. However if you are thinking toms and cumbers that should not be to much of a problem as you could bend them to fit the profile.

[rary]

As greenishfing says take photos and use permanent marker pens to mark or number all corners and bracing struts, it may take time but worth the effort, also if you can use a fan to move the air about you may not need heating in a greenhouse