Hi guys, thanks for your replies ...... despite searching for hours looking for information on the Web, I hadn't found the detailed procedure posted above by Gozomark.
I actually brought my car into Malta last July but, because of frequent trips away from Malta, I didn't get my Maltese ID until last month at the same time I applied for the car tax exemption. I might be caught by a Catch 22 in the legislation: Although I left the UK and "transferred my residence" last July, I haven't yet met the criteria to be regarded as "normally residence" (i.e. 185 days residence in Malta during a year); yet since I am "transferring my residence" it appears that I should have applied for the Registration Tax Exemption within 30 days of bringing my car here. Anyway, today I received an email asking for a load more proof that I have been living outside of Malta for at least 2 years, and for copies of my car insurance going back to July 2009! Like Sheelagh above, if I had known what I was letting myself in for when I brought my 12-year-old Honda down from the UK, I don't think I would have bothered. If I'm turned down because I applied too late, I think I'll scrap the Honda and put in another application for the exemption of a more modern Nissan that I inherited from my dad three years ago (and which is still in the UK). I'll keep you posted on developments.