Just got my nearside sill repaired by Tom Hobbs after recommendations from the forum.
What a fantastic job. The outer sill was heavily corroded and after Tom cut it open that's when the severity of the corrosion became apparent.
Jacking point completely gone and also part of the inner sill. Tom worked his magic and has completely rebuilt the damaged area and resprayed the sill. The final result is superb. Colour matched to car is spot on.
Anyone else who has this problem with corroded sills should check him out.
As promised I said I would post on the forum to make others aware of his expertise.