Old 1970s aluminium sliding patio door - standard size?

We have an aluminium sliding door from about 1973 (according to previous homeowner) and I think it was fitted by Everest. Most other windows we've gradually been replacing in the house from the same time have been pretty standard sizes and we've easily found modern UPVC ones to go into the gap.

Measuring the gap last night, unless there's a much bigger than usual plaster depth (I'll go out this evening in the light to measure to brickwork instead of doing it wall to wall from inside the house), then it's a 2010 wide gap (allowing 10mm for plaster on each side) and I can't find any patio doors that size online right now. Most appear to be 2090 which is significantly wider than the gap I have.

Does this seem right or am I likely to be massively mis-measuring? As far as we know, all the windows and doors installed in the house before we bought it were off-the-shelf ones.

 

Yup, I know that. I was just hoping someone on here may remember/know standard door sizes from the 1970s and tell me what it's more likely to be so I can do some browsing for potential replacements in my lunch hour. Not a problem now though - I'll be measuring this evening.

 

I was pretty much right. Brick to brick outside it's 2010mm wide and 2040mm high including cill. Therefore I think I'm going to need a custom-made replacement as I haven't seen anything remotely like those dimensions online off the shelf. Darn it.

 

Cheers, I just did the same thing. It's £800 for one with two side panels in glass (as wife wants), trickle vents and a few other bits and pieces. Still not a bad price to be honest. Thanks for the tip.