shallow bath waste washer

[Stringman_uk]

Well I bloody cursed it by saying my last post would be my last post.
Just in the process of finally fitting the bath in to seal it and I realised I couldnt find the washer that goes between the bath outlet and the shallow waste

https://simplybathrooms.co.uk/product/exposed-ultra-shallow-bath-waste-in-chrome-11-2/

the part number ht03-10 in the diagram.
I thought I had found a replacement washer from the old pillar tap (well it fitted) but no such luck.
Took the waste apart and rushed to screwfix- bugger its Saturday, closed!!!
So last hour I have been trying to find one.
The sizes make no sense at all to me as some are in mm and others are in inches - which I get.
But when I search for 1 1/2 sealing washers I get washers with 71 outer diameter.

The fitting I have (see photo) has 1 3/4" threaded nut, outer diameter of 44 (poss 45mm) and inner diameter of27mm and a thickness of 8mm
I have searched and searched yet cant seem to find the exact thing that matches,
I found this one:

Flat Washer For 1-1/2" (40mm) Trap Inlet - Stevenson Plumbing & Electrical Supplies

This flat 1-1/2 inch trap inlet washer makes the seal between the trap and waste fitting on your bath or sink

www.stevensonplumbing.co.uk

but that doesnt give me the inner dimension
and also this one

McAlpine 3/4" Flat Sealing Washer 40mm x 26mm - 39004032

McAlpine 3 4 Flat Sealing Washer 40mm x 26mm A flat rubber washer for sealing around 3 4 inch BSP threads including various tank fittings of the

www.plumbers-mate-sales.co.uk

But thought that is not wide enough.
The only thing I can see that actually measures correctly is

https://www.screwfix.com/p/arctic-hayes-poly-pillar-tap-washers-3-4-5-pack/1724j#product_additional_details_container

Would these work?
Or what do I need that I can buy tomorrow

I am already in big trouble as the bath was due to be sealed tonight for Mrs S coming home tomorrow night!

Thanks in advance

 

[avonmouth]

You need a trap inlet washer.38mm i think.Measure inside that nut and see.

 

[Stringman_uk]

You need a trap inlet washer.38mm i think.Measure inside that nut and see.

the inside of the nut (the outside of the metal flange) is 44mm
Sorry that sounded rude, should the washer not align with the threaded pipe coming from the pipe (so it crushes against it)? or should it sit within the pipe?
Thanks