Sean - Hi there I'm not sure if this helps but there is a Sylvia Mona who designs candlesticks for Orrefors glass in Sweden it could be one of her designs?
Mary - I've tried to find out more but no joy yet. Thanks for your help.
LINDY - JOHN JELFS USED J.J.1985- AND A SWAN 1973-
Richard White - Could be John Jones who potted at the Mona Pottery - Llanfairpwllgwyngyll Anglesey ("Mona") in the late 60's-70's but I do not recognise this mark.