A little later, I needed to prepare a wall for tiling, so I bought 5 litres of No Nonsense PVA from Screwfix for about 8 quid.
It appears to be exactly the same stuff - as does Copydex and wallpaper overlap adhesive.
*Are* they all the same, or are there any subtle differences? If I can use PVA for all of these things, my 5L container will last me for the rest of this life, and well into the next! <g>
Click to see the full signature.