Ah okay, will the banjo lines need replacing or can they live on?
I wish I could get a new petrol tank but given the Aerodeck is already very parts scarce in the UK and the tank is different to other 3gens (I believe) I dont think I've got a choice but to try this rust treatment. Bought some of this: Fuel Tank Cleaning Kit | Rust Treatment and Removal for Fuel Tanks - Bilt Hamber
which is rated fairly highly.
Will call Honda tomorrow but I'm not holding my hopes up given they couldnt find me a pan gasket
EDIT: how big are your fuel tanks? mine is 60L, I've seen theres a couple on RockAuto, who knows they could be the same...