How can I check for fault in fuel pump on my 1999 ford fiesta diesel?

I have a 1999 Ford Fiesta Diesel Encore that will not start from cold without an extremely heavy turnover and thick black smoke. I have replaced the oil, fuel, air, and oil filters including glow plugs and done every conceivable test to erradicate relay glow plug problems. I have been advised to pour a drop of 3 in one oil or similar round the glow plugs to check for air leaks from this unlikely source, low and behold three of them started to bubble. Is there any product or sealant that can be purchased to eradicate this? Could this be just the vibration of the engine creating slight air flow whist running ?As this is my last attempt at what can only be discribed as the 'Errol Brown' school of diesel problems (Check his similar problem with Citreon xsara). I am told that Ford have a problem with their fuel pumps for this year and model but of course the real problem with these are the pric. They want 700 pounds for a new one. Come on Ford you caused the problem and this year of car is hardly worth that type of extorsion. Not exactly a happy costomer / happy car parts sale business venture. The new pump can gather dust in the dealership at that price. Anyhar anyone who can help with a more advisable less extorsionate route would be curtailing the full blown symptons of Victormeldrewosis.