Thank you everyone for your replies. I shall definitely get one - electric probably as they seem to have some advantages over the hob top ones.
Yep, stuff like timers, etc. Mine has some type of mechanism in that allows it to start to steam within a minute or so. It collapses into a small space for storage.
Good idea about par cooking the roasties in one Mushroom - I can imagine that works well.
Yeah, the outside of the potato doesn't get overcooked and sodden, reducing cooking time in the oven. And the flavour isn't diluted. Don't underestimate this effect. I was amazed! The flavour preservation was very marked regarding courgette. And steaming is truly the only way to cook rice. Perfect!
By the way Mushroom is your allotment at the back of Prittlewell Chase near the hospital?
yep, that's where mine is
Small world eh