SR Royal Cranks

I have SR Royal Cranks that I bought from Andy at fyxomatosis and I’m running them currently on a Shimano NJS bottom bracket… but I think it’s the wrong length as my bike sounds like a roadie when pedalling a load. Just wondering if anyone here can let me know what length of BB spindle I need to get my chainline perfect with a Velocity wheelset.
Thanks in advance.

have a look here

http://businesscycles.com/tr-refspec.htm#cranks