GRO-BAG TRAYS?

[antatoo]

Does anyone know where we can get the trays to put gro-bags in?
We got some tomato gro-bags from Ferreteria El Real but they don't do the trays to put them in.
Got fed up with trying to grow them in our awful garden soil and have some lovely plants grown in pots now. Just need to re-pot as they're getting very big.

Any ideas?