Question Author
Sigh! Having read (but not processed the thought properly),as to Moira's suggestion of the island location, I initially connected St Mary's Island Chatham to London LCY - (not London Bay) - then looked at the map and route directions to the Orkneys (via St Mary's Whitley Bay) which was, more or less the right heading . Unfortunately, the result was a written response which was simply urble, burble, blurble, blurp! A C.R.A.F.T. (Can't Remember A Flipping Thing) moment. Sincere apologies to all . . .
Senior Moment or C.R.A.F.T. (Can't Recall A Flipping Thing) - sorry! Will endeavour not to let it happen again