Case for Conn tranny

Hi
Apologies if this matter has been raised before, but.
I have recently bought a Conn tranny, a 258 serial number, which Bear at Cybersax says is a very late tranny and one step removed from a true 6M.
Lovely horn and I am very pleased with it. However the case that came with it is neither original nor very good.
Can anyone please reccomend a decent case that will fit it that is readily available in the uk.
I have tried a couple of modern cases and it just wont go in, the table key stack and the left hand bell keys seem to be the problem.
Really I would like a rectangular case with plenty of internal storage and an end as well as top handle.
Weight is not a problem, I am much more concerned about protecting the horn cos of its fragility with having a rod bell brace.
If anyone has anything secondhand that will definitely fit I am interested.
Hope someone may be able to help,

Thanks and regards

Richard