Hi I would just put catapult into ebay then serch them all I did this and got a brand TT whopper dropper for about £4 it was not listed as a trev tomlin .
If you know what the river pult actually looks like then chances are you will find the same thing on ebay.don't bother with the tt whopper dropper rubber pouches I did and it is almost worn out after about three sessions waste of £3 .
Best elastic is the drennon red groundbait then best pouches are from tackle box green ones .