Might be 28mm.But at the moment they've got the chrome pipe going into an 1.25' compression bend and its just flopping about in there all loosey goosey! So its defo smaller than 32mm
I am assuming by north of the river you meen the north bank of the thames you'd freeze to death if you ventured further north than there.
No major problems nothing good old Pete hasnt been able to sort for me.