Your profile says you're 33, you could go for a DAS and have your choice of any big bike? You're going to have an easier time finding something that suites you if you can ride anything.
If you want a 125 then the Honda Varadero is pretty big.
tbh a 125 isn't going to be much fun @ 22 stone! Some nice big cruiser would go nicely.
well i used to be fatter, 29st managed to get down to 22stone after torturing my self. wife rewarded me with booking my CBT when i hit 22stone. btw i am also 33.
my advice tell the place you are big and 22stone.ask them if they have some thing more suited to your size like a XR 125.
the school where i took my cbt initially gabe me a CBR which imho was no good and riding in the yard it was VERY uncomfortable. they noticed this and took me to one side and asked me not to call it quits and to back the next morning, so the next day they gave me an XR 125 to ride on.
straight away i felt at ease, my belly wasnt pushing my legs wide, u-turns were much easier as was figure of eight. and due to the ride position i wasn't looking at the tarmac as much and getting the wobbles.
after my they gave me a certificate they preety much told me to go for a Varadero. way out of my budget at the time i looked at other bike, test rode a few different 125s then rode a vardero up a very steep hill.
so i splashed out all my savings on one and am enjoying it a LOT.
hoping to do a DAS some time after May.
even if your taster sessions doesnt go well don't call it quits.
oh and you havent started to look at jackets and pants have you? sizing is nightmare. compared to normal clothes. jackets wise aussie bikers cater for big blokes, ive given up looking for decent textiles pants postage to send them back costs too much i spent around £90 on postage . Dragging do kevlar jeans for 48" to 50" waist but no knee protection but its comfortable if you know what i mean.