I'll have to do a fair bit of digging to find the kits. With the recovery time from my operation, that may be a while (48 hours before I can drive, two weeks before I can do any lifting more than 10 pounds - and some of the storage boxes in the local stash exceed that). If you need me to go looking, I will as soon as I can.
I just checked on Ebay, the Airfix Harrier GR.5 and Harrier GR.7 kits have six BL755s each and there is one seller who has several of the GR.7 kits for a reasonable price. Worse come worst, I'll buy 3 or 6 of those, ship you the BL755s and fit other armament to the kits and/or do some whiffing for other variants (for example, bits and pieces from two fuselages to make the lengthened one proposed for a "Harrier III"). Considering that you are in Australia, the shipping won't be inexpensive (ask Zack what just a 1/72 A-7 canopy ran me) but I'm sure we can work something out.