Well!

Crap ... I wore out my rear tire ... I wore it right down to the canvas after about 870 or miles and got a flat on the way to work!

Luckily there was a Halford's where I bought a Schwalbe Lugano (23 x 700) and a new tube and had it installed ... for £28.

£15.99 for the tire (Schwalbe Lugano 23-622)
£3.99 for the tube (presta long)
£8.99 for the 10 min service

£28 is $46 today ... so I'll add that to the running costs with the next update!

edit: that's karma biting me in the ass for being a rabble rouser in the other thread!