The error your encountering is probably due to a lack of blood going into the strip. On my GlucomenLX plus meter it's E-4 or something. It happens when I kind of miss the strip and it only takes some of the blood that it's meant to. The associated finger pricker I had no problems with and had been using it for over two years.
Currently, I'm using the Freestyle Libre - but when driving or double checking Libre readouts - I use the Dario Smart Meter. It's TINY and integrates with your smart phone via the headphone jack. For me, it's size it's the game changers as I no longer require a bulky pouch to carry my finger pricker, reader and test strip pot. The good news, it's cheap at £14.95 for the device and x50 strips. The better news, is that lancets and strips are available on the NHS (providing you live in the UK of course). As long as your new chosen meter doesn't incur an increase in cost for strips, etc - then you should be fine getting your prescription changed.
There are many, many readers on the market so google searching will give you plenty reviews and the like.
Good luck,
Grant