A pair of pressure fit stair gates – Great condition - £10 each
They are Lindam Stair Gates ‘Easy Fit Delux Plus’ the same as this:

http://www.amazon.co.uk/gp/product/B000S...UTF8&psc=1

Also offered a 7cm extension piece with it to make the gate wider if you need it
http://www.amazon.co.uk/gp/product/B002E...UTF8&psc=1

Also I have two packs of Y shaped brackets, so that the gates can be attached to staircases that have spindle banisters (e.g. Victorian bannisters)
http://www.johnlewis.com/babydan-y-spind...mcampid=73

Collect from Forest Hill SE23 2ST, or I might be able to drop them over if you don't have transport and live locally.

PLEASE check the width of your staircase first!! The standard gate adjusts to fit openings from 75cm to 81cm, but the extension piece does make it wider.