I knew nothing about it until this morning when i was looking on ebay and thats when she told me.

ive told her that id rather have a couple more dogs before she gets me something like that.

Good answer 

I know I'm biased as my Husband designed the quadriga, but you may as well get one of them to start off with and you are set for years, and it will be just as safe with 2, 4 or 6 dogs or even 8 if you are feeling really keen.

That's blown your £400 budget then!   

Actualy when we go yondering we use 3 bitches on the quadriga, he has the three wheel and the other three bitches and there isnt a huge difference overall.  Effort evens it up 

Must admit I find the quadriga overkill for 4.. although I'll probably run the pups on it this season as it may well be my only rig; I think it depends on the quality and attitude of your team, but I'd find it bloody hard work pushing one round after 2 ambivalent dogs.. (mind you, the same would no doubt apply to a 3 wheeler, realistically!).
Bigger teams, however, yes, 8 on a quadriga no problem  (just show me a rally where I can run them.... ).

Certainly there is no doubt that the quadriga is the safest rig on the market, at any rate;  ;)at the end of the day we all have our own ideas of what constitutes a good run and if people are happy to run smaller or slower teams on a quadriga that's fine !