Wilf,
Sounds very similar to the problem I had a while back on my 2000 TD5. From the location of the leak, it will most probably be the fuel pressure regulator valve leaking or if your lucky, maybe just a fuel hose. If it turns out to the fuel regulator, a new assembly (plug in regulator valve not sold separately from housing & hoses) will probably set you back about £85.00 and takes a bit of replacing. If you haven't worked on the TD5 engine before, it will probably take you a good 6 hrs to do the job, unless you can manage to get your arms down behind the engine to reach the unit without too much stripping down. When I did the job, I did it the hard way and had to remove the exhaust manifold, fuel cooler, etc. and even then, I found it quite tricky.
Hope you find out its something cheaper and simpler !