What is the actual problem with your loom? The issue with the original engine wiring loom was that the insulation to the wires was sub-standard and disintegrated in places. If this is happening with your loom I would suggest that it has not been replaced under the recall as the insulation to replacement looms was to a better standard. You can check by putting your VIN in
https://recall.porsche.com/prod/pag/vinrecalllookup.nsf/VIN?ReadForm&c=gb
However, if it doesn't come back with any recalls don't assume all have been done. I checked my car a few times and it always came back clear but just a couple of months ago I finally had the wiring recall carried out after presenting Porsche with the evidence that it had not been done.
Look at the wiring loom label inside the rear fuse box in the engine bay on the left hand side. That should give you the part number and a manufacture date, I can't remember what the cut off date was (sometime early 1996 I seem to remember) but the part number you quote above is for one of the looms that should be replaced. Have a look on-line, the American technical service bulletin is available at
http://members.rennlist.com/pcaracing/files/harness/NA_Harness_TSB.pdf but you'll not find the GB one anywhere - not even Maurice has a copy of that.
If you have the original self-destructing loom I would advise not driving it anywhere until it is replaced (not even to the garage to get the replacement loom) as the problem can cause many issues, not least of which is the car self-combusting, either through a short creating a wiring fire or a short causing the injectors to over-fuel, resulting in petrol building up in the silencers just waiting for the optimum stoichiometric conditions to occur. And then there's all the electrical circuits and components that are connected, either directly or indirectly to the engine wiring loom...
The replacement loom is part number 000 043 204 61, which fits all models except the turbo but this is a Porsche Centre only part and you will not be able to purchase it.
Good luck