Trampoline sizes advice please- 5yo and 2yo

[mammymac]

I'm thinking of getting my DS(5) a trampoline for his birthday. Inevitably my 2yo DD will also be on it.
I'm struggling to decide what size to go for. We have a big enough garden to go for a 12 or 14ft one. However, I wonder whether they are a little small for that size (especially the 2yo) and also am baulking at the price of them a bit if I don't need to go that size. 5yo has had a great time on a 6ft one recently and B&Q are doing a good deal on an 8ft one (£90)so I'm tempted to go with that. But do you think I'll regret not going bigger?
I'm imagining that in e.g. 5 years they may want a bigger one and by then it might be time to replace it anyway.
Any thoughts please - going round in circles just now and birthday is next week!

Asda did have an offer on a 10ft one with net for £96. My two (7 & 3) play fine on that size as do the two teenagers next door (16 & 13) so I think it should last fine.

Wow that is a good price but I've phoned all the stores in the area and they are all gone. Shame.
Guess we're back looking at the 8ft one. Any thoughts anyone?

We got a 14ft one for a nearly 2 and nearly 4 year old last year and they loved it.
Thought dD2 would be scared at first but not at all! That size is probably not necessary but not a waste of money either. I think probably safer for 2 kids to go on a bigger one - less risk of crashing into each other?
Can't remember exactly how much but think it was around £100 - very good offer from Toys Rus including the enclosure.