swivel seat forward wont lock

hi my mercedes devon driving  swivel seat won't lock in the forward driving position is there any ajustment  anywere

With our 2009 Duetto we had to insert pegs  into holes in the passengers rotating base swivel, dowling rod or metal pipe worked fine.
frederic
But that was for rearward facing.

Our Pollensa has an orange handled lever on the side to release the swivel, sometimes it needs a bit of a clonk to engage properly when returning to forward mode.

were do i buy a clonka
it is ok job done you return the seat to forward facing before sitting down, sorry only just got it.