Compression Waste is Universal, it will fit any pipe of a similar size, so wherever you want to change from Push Fit to Solvent Weld, fit a Compression joint and continue from there.
It is the join from the white Push Fit to the Grey pipe I would be concerned about in the first instance, if they've joined to ABS with a Push Fit coupler, then the integrity of that joint would be questionable.
The outside appears to be pushfit.
I'll be replacing everything from the compression 90 outwards, probably in black 40mm - Just need to size up what additional parts I need then it's off to B&Q (With Screwfix 500 yards away it's still cheaper at B&Q 5 miles away.).
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