I did quite some research on this in the past. I have quite serious preserving attitude. Not a very bad habit in todays world imho.
Both my SAAB and all my steel bike I did with Mike Sander and FluidFilm.
There exist various FluidFilm products. View them here =>
http://www.fluidfilm.de/produkte.php (sorry, in German)
They are oils and Liquid A is the most fluid. I spray them in with comprossor and spray gun. Great for parts not easy accesable and to immediate attack rust.
There also exist AS-R aerosol spray cans. Great for bike use! AS-R is a bit less fluid and more durable than Liquid A. About 8 euro a can. A 40cm nozzle costs an extra euro.
The ultimate rust preventive product for the long run is
Mike Sander. It is a grease that has to heated up to 100 celsius. You heat it up on a stove or in a water boiler. Moreover you need a quality (pressure) spray gun and a compressor.
Here a review of various rust prevention products =>
http://www.citroen.ac/downloads/2002_10046_Rost.pdf
I doubt whether products of both manufacturers are available on the UK market. They weren't available in Holland too back then, so I had to import quite a lot of the stuff myself.
Bottom line it is quite an investment in money, time, energy etc., but if you have many bikes and nice car (or more) and you would like to preserve them (and those you acquire in future), an investment worth consideration maybe.