Bed supports on Stratford (and others)

Hi folks, I am sure someone has overcome this problem previously but I can't find a thread. One of the black plastic inserts in the pull out sections between our rear benches has broken leaving half up the square leg and the other half with the adjuster is now not attached. Is the best idea to jam a length of wood up it and drill the end for the adjuster to go in? Or are new adjuster blocks stronger. This design has been around since Adam was a lad so I hope there is a good remedy. Other makers seem to make a better job of this design of pull out slats - has anyone changed the whole assembly? Cheers.