I assume you are talking about actual preserving jars, rather than jam
jars. You can get them from Lakeland Limited:
www.lakelandlimited.co.uk

thank you everyone for the advice . Are these okay to boil? I was a bit
concerned that the rubber rings might melt or something - I'm sure this is a
stupid question but I wasn't sure if these jars with rings were actually
intended for preserving or were just for show IYSWIM

Incidentally I'm not necessarily looking for "posh" jars, it's just that
I've never tried this before, or in fact eaten bottled fruit before, and
figured that my best bet woudl be to try doing it using the "official"
equipment first before embarking on anythign more inventive, that way I'd
find out what it was supposed to look and taste like and woudl have some
basis to compare my future, probably more opportunist attempts to IYSWIM
Hayley