Setting up an archive is something I’ll look more if it is the favoured option. Shifting them to the bin was just the quickest option to begin with. They’ll be set as a sub-forum, just closed (I think people can read closed forums).
Something else I am going to do is change topics across to the new forums. As there were hundreds of topics and each had to be done individually, I was going to shift across those that were requested. The bar topic threads are definately ones I can start with.