Thats OK, I wasn't sure which way you were aiming. TBH for a top of the stairs gate I would recommend something like this if you can get one wied enough as I (personally) think that the trip0 bar on the modelyou showed is dangerous at the top of the stairs.
I know that it cannot always be done though with the gap size.
thanks. we've actually gone for the lindam extending metal one (£17.99). it isn't much to look at, but extends wide, no trip bar and is screwed to the wall. fingers crossed we get on ok with it! thanks for posting