bokkenrijder, if you read the whole thread you will see that I write here because I have intimate experience of the situation. Some years ago I foolishly tried the same tactic. When I eventually returned to the UK just prior to my planned retirement, I was presented with a self assesment tax form and a letter from my local tax Inspector.
There is no way to fill it in without admitting that you had incomoe abroad and no way to avoid telling them that you have paid no tax on that income.
Result after long and painful negotiatoins; retirement postponed to work full-time to pay the unpaid tax, the penalty (50%extra) and keep my body and soul in one piece, 16 year old car, living in a caravan, no house, no holidays, no extras!
I am not jealous of those in the same position as I was then, I am simply trying to prepare you for the inevitable outcome.
I will finally retire next year to a shed on the beach in Thailand so I am past caring.