Hello Pete, that is exciting.
I carelessly brought red spider mite into my tunnel on a bought cucumber plant, in the tunnel’s first year on virgin soil. But my tunnel at Lower had 15 years without any of that pest.
Tomatoes crop a little less vigorously every year, I think from root predators in the soil – but you can keep growing them without changing soil and I think French marigolds help. I do a two year rotation for tomatoes, growing cucumber, melon, basil every other year. Though in a 12×8 its tight for rotating and plant roots travel laterally a long way.
A nice time you can have, seeing what happens, and your high-quality compost will help.