27 months and newborn- do I need a double?

[SuiGeneris]

DC2 is expected in April, by which time DS1 will be 27 months. I am hoping to get by with a sling and pliko switch for the first few months and then said pliko and a buggy board. We live in London and mostly walk or take the bus. Is this feasible, do you think, or Should I look to borrow a Phil and Teds or in-line double?

I tried my 3.4 up year old on two buggy boards today and a) found them heavier to push than a lot of double pushchairs b) I now have back ache because although I push one handed in the middle so therefore walk at one side anyway, i must have still been leaning or else the extra weight as affected me and c) on one my daughter rocks side to side and we couldn't work out where her head could go and the other she slipped off twice and the second time banged her mouth badly and she ended up walking. If you get a buggy board try to try it on your pushchair and work out where you will stand, how you will push and where your feet will, where your child's head will be and importantly where they will hold onto. I have to say, I prefer a double pushchair. After DD fell off the second time in the supermarket it all went horribly wrong...a double at times is just simpler although may well not be the best option for a bus, but it can be done.

My age gap is smaller (21 months) but I would say yes, borrow one if you can. I tried without for a while and it was just too hard physically and logistically. Having somewhere to stuff 2 screeching children and just GO is invaluable, IME.