Why can't you just extend the existing ring?  Extent the loop ring from where the fused spur is currently. this assumes the fused spur in on the ring. Peter

Why can't you just extend the existing ring?  Extent the loop ring from where the fused spur is currently. this assumes the fused spur in on the ring. Peter

If the existing ring circuit does not have 30mA RCD protection it could not be simply extended. Making a new ring from a single fused spur is pointless you would need an RCD spur for both legs of the ring ( if earth continuity R2 is lost and a fault occurs it's a 50% chance whether it will trip the RCD or not depending on what side of the RCD its on. Unless you plan to run sizeable heaters a 13A  radial power circuit would be plenty for table lights, TV, etc.

Phow said:

Extent the loop ring from where the fused spur is currently. this assumes the fused spur in on the ring.

Who said anything about a fused spur? However, SRCDs may still be available. We discussed them 4 years ago: engx.theiet.org/.../omitting-30ma-rcd-protection-for-single-s-o-in-a-domestic-property

The only sensible place for an RCD on a ring is at the origin - the behavior of RCDs in parallel is not well defined, and you do not want RCD operation to open the ring and leave part of it alive. However an RCD spur or at most two with fuse 13A or MCB of 16A each with the RCD covering the spur but not the ring part would work. If you have expect more load than this then really it is not suitable for extending the ring anyway. This is only kicking the can along a bit, and probably not worthwhile - the 'proper'  solution at some point will be a new CU with RCBOs or RCDS inside it and take the chance to bring the rest of the installation into the 1990s safety wise..