Is the covering acetate original to the print, or something applied later?
If it's added, it may be possible to peel it off, though exposing the print to air may accelerate any color deterioration. The color looks pretty good now, so taking the coating off could compound your problems.
OT here, but a digital restoration is entirely feasible, it doesn't look to me like it would be all that difficult. Then you can concentrate on conserving the original rather than restoring it.
Simon Galley from Ilford may pick up on this thread, if not, I'd try contacting Ilford and get their advise as a first step.