Hello
Lilly launched an insulin pen called the Humapen Memoir but as yet its not available in the UK. It has a digital display and also a memory function that will record when the last dose of insulin was injected etc. Unfortunately, it does need two hands though.
An alternative for your mum would be the Owen Mumford Autopen. This is available on prescription and works with Lilly and Aventis insulin cartridges. Unfortunately Novo cartridges wont fit. The pen has the release button on the side and can more or less be used one handed. It is ideal for those who have dexterity problems.