Have spoken with the tax office. They said to send in a letter explaining what I did for a living, who for and for how long.
Understand that you can backclaim for up to 6 tax years which fits perfectly into my civilian career but, as this FRE was dated for the 2006/7 tax year, what was the annual amount available for the years prior? (Surely they don't just take the new FRE figure and multiply it by 6, or do they?)
Anyone successfully backclaimed and how did they calculate for the years before this FRE?