new door handle bar not fitting mortice latch

Hi,

I've purchase some new door handles from screwfix:

These:
http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A432942&ts=67752&id=90855

but the supplied bar does not go through my original mortice latch hole, the bar is too thick. I realised that bars could be of different lengths but didn't realise that the bar could be a different diameter. I need to replace all the mortice latches anyway because I am changing from brass to chrome but don't want to order new latches if the bar isn't going to fit.

Are the holes in mortice latches supposed to be a standard size and I've just got a dodgy set of door handle bars. The bars are not solid all the way, they are cut down the middle on each end to accommodate a grub screw but I don't think this makes much difference.

Is your old latch a Tubular Mortice latch, or does it have a squareish box and/or a lock?

Its a tubular latch with no lock. I have to buy new mortices latches anyway but looking on screw fix it doesn't mention anything about the size of the hole that the bar will fit through and I don't want to buy 11 mortices latches only to find the bar of my handles do not fit.

I though latches had a standard hole 8mm square.
(see example http://www.screwfix.com/sfd/i/cat/pdfs/16/p3638116.pdf)

What size do you make the bar they've sent you?

Majority are 8mm, with a few mortice locks that take 5mm/7mm spindles. I'd take a file to the bar and reduce it.