We used to have an arangement with supply authority whereby they would sell registered contractors some numbered plastic seals (yellow),and if you unsealed cutout you resealed with your plastic one and notified them & they would change for metal (nomal) seal later.
since privitisation they won't play, ECA & other orgs . keep trying but dealing with several energy suppliers not easy,
Officially u should talk to them first, the reason seals there to stop tampering with supply, not forgetting if you make a mistake on pulling/refitting fuse several thousand Amps can flow until short circuiting item vapourises........B.W. SPARX