40mm PVC waste slip on coupling? Or alternative?

Hope someone can help!
Renovating bathroom and I have to connect a linear shower drain (Schluter https://www.tilingsuppliesdirect.co.uk/product/schluter-kerdi-line-g3-linear-drain) that will be glued in (tile adhesive) to pre-existing 40mm PVC waste (light blue in picture).
The problem is: the pre-existing 40mm PVC pipe is rigid and once the linear shower drain is in it is rigid too. Therefore, using couplings with cement doesnt work (or I cant see how) as I can not move parts a apart to slide them into coupling.
An yideas appreciated
- I was looking for a straight coupling without a central stop to slide over first, new pipe in place, apply cement to both ends and slide over > Cant find such a thing
- 40mm straight compressin coupling, again: can not find one I can fully slide over one of the ends without a "stop" in the middle)
Thanks a lot
Simon

denso13 said:

https://www.screwfix.com/p/floplast-wf08-flexi-waste-straight-coupling-grey-38-45mm-x/81383

Click to expand...

Thanks. I saw these but I am not sure / have no experience if these are safe to use in a concealed / inaccesible area?

SimonTheGerman said:

Thanks. I saw these but I am not sure / have no experience if these are safe to use in a concealed / inaccesible area?

Click to expand...

Yes, the clamps ensure a solid connection, unlike push fit for example.