Are you sure its a spur from a ring, and not a radial circuit direct from board? (likely 32A breaker if ring, 16A if radial)
If it is a spur from a ring, can it be modified to become a fused spur? (unswitched fuse plate next to socket on ring before the branch)
As this thread, and the other similar thread linked above, the letter of the law in the regs book says no spur from a spur, and it mentions "points" whether that be a socket, or in your case a fused connection.
Safe, but not technically compliant.