The wife fancied a new cellphone, fair enough, she's had the old one for years. Unsurprisingly all the new ones have at least a microSIM card, if not a nanoSIM, and Vodafone will replace cards for free if you have a contract but we do not so they are not keen. (We both use Vodafone because it allows calls in most of Europe and New Zealand with no messing).
I looked at trimming her standard card to fit and the internet gives loads of pictures, some are suitably vague and some completely misleading which would lead to destruction of the SIM card but this is the best and most sensible:
MicroSIM_cut.jpg