Thanks everyone.
I guess I was initially favouring the 3 wheelers simply for looks, but I am looking at 4 wheelers now also based on friends' advice. I will be doing lots of outdoor walking with the pram, but mostly on footpaths and sometimes roads- nothing too rough. I will check our the valco reversable with toddler seat- thanks for the advice. The only other pram I can find that is reversable, outdoorsy, with toddler seat option is the Bertini X4 Lite. I'm not sure of the cost, but it looks as though it would be a pricey pram...