Easiest way to approach it I found was to go through the whole paper and answer what you know without the aid of the BRB, then go back to the start. Time will be you're worst enemy if you don't know where to look in the book, so don't dwell on a question too long, come back to it if you have...
If you're asking is a 4mm radial ok, then the answer would be yes, but from what you describe I would do some further investigation of where this other leg of the old ring goes/comes from. Does it still feed any other sockets?
From what you say if it's wired in 4mm, it sounds like 2 radials off...
Citreon Dispatch 1.9TD. Great van, 2 side doors, fantastic heater!
Just had it serviced and new cam belt at 137,000 miles. Pulls like a train and plenty of room inside.
Would definately have another.