Is there a compatability issue between a Shimano chainset and a Hope BB? My old RF chainset worked fine with a Hope BB and it was easy to achieve the required 49mm chainline. Not so with my new Shimano XT c/set so do I need to go back to a Shimano BB?

The Hope Bb shimano chainset should work perfectly. At least they do on all my bikes. Have you got the spacers in the correct locations?

1 x 2.5mm spacer on d/side BB. The problem is that I am unable to set the d/s close enough to the BB to achieve the desired 49mm chain line which results in crap shifting and constantly dropping the chain off the inside. I’ve temporarily gone back to the RF set while I think about it!

For a 68mm BB shellit should be two spacers on the drive side and one on the non drive side. For 73mm shell its just one on the drive side.

No compatiblity issues here and I’ve got Hope BB’s and Shimano XT chainsets on two bikes

My Hope BB is fine with my SLX cranks.

Aren’t most modern bikes a 52mm chainline or similar? Perhaps thats the issue and you need to play around with the spacers?
What is the width of your BB shell?
68mm will need 3 x 2.5mm spacers (2 drive side, 1 non drive side)
73mm will need only one. (1 drive side)
You can swap them about a bit, so perhaps give that a bash?

73mm BB shell. Orange quote a 49mm chain line which is easy to set with RF. Shimano quote a 50mm chain line for their new chain sets which I imagine will not cause any major issues. Set up with 1 x 2.5mm spacer on the drive side BB which should work perfectly but does not. Going to do a bit of swapping around with another bike to see if I can resolve the issue and work out what is causing the problem.

Mine’s on an Orange 5 and set up 1×10. I’ve not really looked at the chainline, but it all works and there’s nothing too obviously out of line, otherwise I’m sure I’d have noticed.

If its a 73mm shell, you could try playing about just one spacer on the opposite side instead to see if that improves the chainline.