David wrote:

Ikea adapter has an outside diameter of just over 40mm and an inside
diameter of about 36.5mm according to my digital callipers.
The old push fit is marked as 1 1/2". which is roughly 37.5mm.
New flexible pipe and old fitting seem to roughly match at around 37mm
external/internal. We can but hope.

McAlpine multi-fit straight connector or elbow may be your friends,
wonder if "european" is their code for "ikea"

https://mcalpineplumbing.com/plastic-chrome-fittings/multifit-waste-fittings