Thanks to everyone for all your responses, the power of 'Mudcat', so!
I was particularly interested in the comments about the use of 'so' at the end of sentences in Ireland which I hadn't really noticed until I moved here 15 yrs ago.
For those of you whe have the time, can I recommend an expert on the correct use of the English language, Neville Gwynne, who appears on BBC Radio 5 Live's 'Up All Night' programme, early on Monday mornings (from 01.00).

https://www.youtube.com/watch?v=kUriLAeu3IQ