However, if the pilot was flying on a UK issued JAA license rather than a FAA cert - then he would have been restricted to only flying in UK airspace (in accordance with FAA regs).
Hence why he might have been VFR and remaining N of the border.
Yes a direct route would go via the Shannon FIR and thus would require a flight plan so with the absence of a flight plan it would appear that the aircraft was intending to route clear of the Shannon FIR.
I had thought of the Licence / Reg issue but even routing around the Shannon FIR would cause the flight to be outside the UK during part of the flight (especially over the Sea) so if that was the case then I am sure the pilot would have remained in the UK at all times i.e. route via Scotland.
How easy is it for a pilot who wants to fly direct in such a case to file a flight plan from a remote location these days i.e. with no fax or AFPEX access? Would the hassle be enough to discourage a direct route?