In reply to Andypeak:
Hi Andy, I work on a few Ultra's across the UK.
The base requirement is usually having the GPX downloaded/saved to your smartphone (saved to OS Maps / Komoot / AllTrails etc..) - this course should be marked but if in doubt you can turn location on and verify via your phone GPS.
Event organisers might advise differently, but I'd imagine you'd get some funny looks if you took out a physical map mid route.
Best of luck for the race.