Needed: One-Off ECU Shipping to UK

[Citroënbender]

I have a problematic body module, it’s Italian but an English company (ECU Testing) think they can likely fix it with lifetime warranty, no re-initialisation required. This saves me fees at the return side; no programming, retention of access codes, the radio works without hassle and mileage (high) is honest for a vehicle identity check.

With their T’s and C’s, comes this constraint:

Please Note:
If you are sending a component for testing from outside the EU (European Union) we will not accept ANY package that incurs customs duty, please take this into account when declaring a value of goods for customs. Any parcel that incurs any import duty will be refused and returned to sender.

I feel that rules out Oz Post/Royal Mail as they aren’t going to tango with me if it gets pinged for import costs.

Has anyone here, more recent (post Brexit) experience with a similar situation, and have a carrier to recommend?