I've had a few ATVs and they can be great fun but this last 10 years or so there is a lot of chinese junk with no parts support or QC flooding the UK (or more accurately ebay). You may end up with something that can not be repaired or at worst is unsafe. If you fancy a quad or buggy may be worth sticking to the big brands. I've always had honda and no complaints. Personally I don't like the idea of road legal quads - quads are for off road use and are in my view not very sensible for roads.
As for whether your wife would enjoy a novel wedding vehicle only you know the answer to that.
yeah im seeing loads on ebay, and i can imagine parts will be a pain,
skidder, with these type of road buggy's what sort of mileage can you take them on, do they suffer with overheating or are there general rules with distance or engine running times?