I might try this fairly soon. I was also told, if you are tight-arsed about doing it properly, you pour a litre and abit of kerosene into the gearbox once the oil
has drained. Start the engine and push the gearstick into gear (without the clutch) so its resting on the gear but not actually going into gear. Apparently this
engages the synchros and cleans them. Once done drain the kerosene, fill it up with oil + some nulon G70 stuff and should be good
Ill be doing it soonish so ill post it up on how it goes