Sink overflow to waste disposal

[cdbe]

Any suggestions? It's an insinkerator evolution. The overflow pipe at the top is about 30mm diameter, the white screw cap is the inlet on the disposal (looks suitable for a 25mm pipe - presumably the cap is replaced by a compression nut and rubber seal.

I think this has been asked before without being solved, so alternatively is there a universal fitting that would connect the 30mm pipe into a standard 32 or 40mm waste fitting?

 

[jj4091]

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[Justin Passing]

This is from Wickes. Worth a try - slice out the inner thin plasic tube with a penknife if it's in the way.