Looking for a pipe fitting

Sounds like 40mm pushfit pipe - which means you need either pushfit or compression, so screwfix 79721 or 35203.

Just to add, the existing pipe was connected to a waste trap under the floor, but now I will be fitting a new waste trap above the floor as the shower tray is on adjustable risers.

Yes, waste compression fittings are very accommodating - it should tighten down fine.

Strange that the pushfit is too loose.

This sounds like a standard 32mm fitting. What you might be finding is the internal diameter isn't fitting inside a new compression fitting because the older pipe doesn't allow for the extra width needed to accept the male pipe inside the modern compression fittings. The older compression fittings didn't have the male pipe inside them and the end of the pipe just pressed against the inside of the fitting. You should be able to get a 32mm solvent weld fitting to press on to the pipe with no problems.

All the solvent weld waste pipe I've seen is grey (Terrain etc), not white. White usually uses some form of push on fitting. And these pipes have a different OD. Also, older push on systems weren't necessarily compatible with one another. Not sure if they are these days.

You can definitely get solvent weld in white ABS - I have some! e.g. screwfix 19362.

Yes, the 40mm waste 'compression' fittings are design to be able to be used with both 'push fit' and 'glued' 40mm pipe.

Grey, white & black :-)

and PVC and MUPVC.

(The PVC's solvent weld better than ABS in my experience.)

Problem solved. Put short section of pipe in lathe and took a skim off it, then solvent weld onto elbow. Best joint yet.