Demon Tweeks was the first place I tried and they said we'd have to post the hose to them. They would then post it to Goodridge who would then send the details to someone else to make it then send it back to Demon Tweeks. They had no idea of price and said it would take AT LEAST two weeks.
I'm sending it to a Goodridge agent called Oakbray Engineering who are going to have a go at it. If they can do it, I'll post the details here so at least everyone will know who to go to if they need one.
By the way, the Alfa dealer quoted £300 to supply and fit as the bulkhead end is a pig to get to. Thats the reason I'm asking them to put a banjo fitting on that end, so I can use a 1/4 drive ratchet to fit it instead of repeatedly trying to put a spanner on a fitting I can't even see. It will also reduce to risk of damaging the pipe as I won't have to bend it round 90 deg to get it to fit.