G'day LukeSW,
My understanding is that to convert a licence, the country of origin licence I.e. UK or Qatar must be current at time of conversion including medical. If Qatar is ICAO then it shouldn't be a problem.
Check out the link on the
Civil Aviation Authority of New Zealand website under pilots and foreign licence conversion. if anything, there should be an email addy for you to contact someone in the office direct.
Also... cos you haven't used your "lifetime" licence for over 5yrs i.e kept it current by way of BFR etc. Your licence is considered invalid til you pass (in your case) CPL or ATPL law and do a re-issue flight test (maybe a BFR... but a flight test of some sort anyway).
thinking of coming home??
Happy new year to you too!
Cheers
S2K