3 wheel / 1 piece / umbrella fold Buggy : HELP

[MrsH2010]

Hi - I need some help.
I'm looking for a new buggy for my 9 month old. I want a three wheeler - so it's good on our dog walks and not just on flat pavements in town, but one that is a one piece unit (not detachable chair part etc just to get it to fold down) as on trains/buses/travel this will be a pain.
I know the old-style Quinny Zapp used to do this (3 wheel, light, easy fold in one piece) - and then they changed it to be a two-way seat, and made it detachable as a result... so that's out!
I'm going round and circles and wondering how on earth finding a (simple!?) buggy for a baby can be this difficult.
Can anyone help??

baby jogger city mini

EldonAve - quick off the mark! Thank you... Do you have/have you used this? I had swept past it quickly, but had stupidly presumed the 'city' bit made it less suitable for all terrain walks etc Any first hand experience would be greatly appreciated!

or you could look at mountain buggy or nipper

EldonAve - I went out and looked at the Baby Jogger City Mini today -amazing that when you're looking for one they're everywhere - the woman who pulled up next to me in the carpark had one, so I pounced like a mad-woman and asked what she thought. She was going back to by the double version as she's expecting again - so I guess that says it all! Had DS have a good sit (and suck) - and did a buggy-dash around the shop. Loved it. About to order online.
Thanks for the recommendation - was going round in circles beforehand and didn't think what I wanted existed!