Shower waste hole not quite big enough for 90mm shower trap

[PythonCrazy]

I attended a customers house to fix a reported leak from their shower waste. Turns out there was a split in the trap. Straight forward I thought and got a standard 90mm trap from the van. Turns out the hole in the shower base isn't big enough to fit the top section by the width of the thread on the upper section. When I measured the hole it was only 85-86mm wide. Has anyone else come across this before? The waste that was on there was unbranded and I haven't been able to find an equivalent online. I'll expand the hole if necessary but I thought all shower tray waste holes were standardised.

 

[ShaunCorbs]

Is the hole recessed Does the new trap fit in it eg the indent ?

Could be imperial depending on age

 

[Sam789]

Is the hole recessed Does the new trap fit in it eg the indent ?

Could be imperial depending on age

Did you fix this as I'm having the same problem.

 

[PythonCrazy]

Did you fix this as I'm having the same problem.

I ended up cutting all the silicone off the existing trap and carrying out a repair with mesh reinforcement and superglue. Took an age and I was worried it would leak after a bit but it seems to be holding up ok a year in. The only online supplier I found couldn't tell me when the waste they had that should fit, would be back in stock.