I Googled 'Fire resistant greases' and got the ESSO website fairly quickly. Why don't you contact the larger lubricant manufacturer helpdesks (like ESSO, SHELL, TOTAL, MOBIL etc?) One of them is bound to have what you are looking for in their portfolio. Or is availability in the UK the issue?
Usually the 'big boys' will help specify the right product, and generally e-mail you the data sheets and any relevant health and safety data immediately, and advise you of your local stockist.
I would also recommend KLUBER Lubricant in Halifax, I normaly get sorted by Sandy McClure. If he can't help he wil probably be able to point you in the right direction.
what do you exactly mean with "fire resistant"? just a "grease" that can withstand high temperatures or does it actually come into contact with flames? in the latter case the big oilmajors will not be able to solve your problem, because nearly all their products are based on mineral oil. kluber and other specialist firms then might be more appropriate to consider.
whatever the case: bear in mind that increasing the temperature of the grease will cause it to degrade much faster so more frequent relubrication may be needed.
"grease formulated with special flame-retardant additives. Unlike a fire-resistant fluid, which will not readily ignite, a fire-resistant grease may burn but will rapidly extinguish itself after the ignition source has been removed."
There are all-solid lubricants. Boron nitride (BN) sprays, which are actually mixtures of boron nitride and clay, are very lubricating and all ceramic. Molybdenum disilfide is another choice.
