Thanks for all the replys folks they are all very helpful but to everyone who has bought a space saver where's the best/cheapest place to buy and how much please same for jack . Thanks again

I'm not sure I'd want the jack unsecured - it could be dangerous in the event of an accident. Could you jack it out slightly and put it in under the centre of the spare wheel?

I am going to try that when I have time. In its present location it's jammed down fairly tight by the front edge of the floor, which can't be lifted without lifting the back and sliding it back. Of course, this doesn't apply with the floor in its upper position, but it will only be there if I've got the seats folded to carry stuff. In an accident, the cargo will be more likely to be a problem than the jack.