Hey Sarah, thanks for the compliment!!! I must look like an illegal wannabe immigrant - NOT!!!

Thank you for that explanation Martin although I doubt if I will ever be spending more than 180 days in US in the future, but useful to know. Yes, the IO certainly try to frighten you, and I went though a 2 year period of being hauled into secondary every visit (3/4 visits per year). I knew someone else who had been through the same thing and they were kind enough to give me the information I needed to make the IO stop this nonsense - most of it was to do with my apparent lack of readable finger prints - so I decided that I would give it one more go without complaining.Wow, was I surprised not to be summonsed and lucky not since then. I stand in line rubbing my fingers over my forehead as apparently that is where there is more natural oils for your fingerprints! One learns something every day.