Thanks for all the points to consider. It will be going in a garage at the bottom of the garden, and it's quite built up around here, so it may well annoy the neighbours as well as attract unwanted visitors.

Space is at a premium, so I think the best bet will be to measure under the work bench and get the largest I can fit in. I would like one for sand blasting and spraying as well, so it will be a compromise between these three roles.

Adrian.