many thanks,
took advice from a specialist plumb shop....supplied me with a collection of useless compression adaptors. Ended up trawling through B&Q shelves and found the exact adaptor required: solvent to push fit.
Thanks anyway.
How do I connect a 43mm 'solvent junction' waste pipe supplied with shower trap to a 41 mm push fit drainage system in the existing bathroom. Can't seem to find appropriate bit of kit. Suggestions welcome