BN, you're quite right of course - all plans (particularly career ones) need an element of flexibility built into them. I just think that a pretty fixed time-based plan is req'd whilst training - particularly so when studying for the ATPL exams - otherwise things can and do drift as you say.
Approaching the plan in 'work mode' also tends to keep you focused and timescales short; I would imagine that potential employers would tend to look more favourably at someone who has completed their training in as short a timescale as possible, rather than a stop-start approach. I guess this risks getting into the integrated v mod debate, so I'll stop there!
I will keep options open re overseas jobs as you suggest - Mrs HW seems quite keen on anything that would help escape the UK weather
HW