Does anyone know where I can get a seatpost for the above? It's a weird size of 26.4mm. Can find plenty at 26.2mm.

Cheers

Ooops. Should have said 27.4mm

Well every shop I asked (built one up for the g/f) said 27.2 Ive fitted a 27.2 (same as my ds1) and its perfect....so ide say go for a 27.2.......I assume it's the grey teflon finish frame?

Yes it is. Thanks Chris, that's great:-)