Thanks for the clue on fitting the action to ensure correct alignment Oliver.
It seems the integrity of the Airsporter stock is very reliant on a firmly mounted action. Looking at it now, it is very apparent; quite flimsy
Also on using the thread . Seems I have read elsewhere that compressed air is good to spread that glue through the crack.
This weekend I'll trial out the glues I have on hand on scrap timber; white PVA, yellow PVA (water resistant?), West System epoxy (my sons') and the Titebond3.
I will set them aside for a few days and give them some grief to see what holds best