Is that what you carpet pro's call LM, which I assume and will stand coorected is low moisture.
I have exhausted the research and really don't want to do this but I have no choice, my head is in bits with micro splitters, was told will clean anything, pre spray, scrub, extract, does that mean more equipment, ie numatic over the carpet then extract with cc machine.
I need a drink. 
Hi Claire,
I was in your position a while back and I decided to go with HWE. Its more versatile and will clean pretty much any carpet to a high standard. Dry Fusion and other low moisture systems are great and also have their own role in carpet cleaning but when dealing with a pub carpet I would always go with the HWE.
If you have a steempro why not just use that. i dont understand why you would want to spend between £2-3k on a dry fusion system when you've already got a hwe machine there.
yes it leaves the carpets wet but anything over 6-8 hours drying time is probably down to operator error rather than the hwe (unless its got a mechanical fault). this can be reduced by opening windows, doors to create airflow.
As for the process its not all that difficult and i would do it this way...
Step 1. - good vacuuming all over the carpet with a sebo (ideally bs36) or use whatever vac you have. anything is better than nothing.
Step 2 - depending on how dirty it is pre-spray with either something like prochems pre-spray gold (low level staining), ultrapac renovate (medium to high soiling) or if its really bad something like powerburst or traffic lane cleaner. Put down extra spray on the dirtiest areas and the traffic lanes (ie where people walk). in know people always say pre-test first but the chances are pub carpets are always minging and theres a good chance they havent seen the actual pattern in a while. If you're using powerburst or traffic lane cleaner dont leave it on too long.
Step 3 - you have to work this in with either a carpet brush or if you have an agitation machine like a sebo duo or scrubber/envirodri etc... this will make sure that the pre-spray goes all over the carpet fibres. you could even spray 4-6m2 at a time and go at it with a stiff handbrush if you dont have any of the others.
Step 4 - extract out all of the gunge with the steempro and hot hot water with something like fibre and fabric rinse to neutralise the ph and stop quick re-soiling.
Use your air movers to help up the drying times and go over the carpet with plenty of dry passes (without solution coming out) to get as much of the water out of the carpet as possible.
I hope this helps but HWE really is the best tool for really dirty carpets.