Our car has been sorned for a few

The " ask the police" website [ https://www.askthe.police.uk/Content/Q600.htm ]says;-Q600: Can I drive my car without an MOT? No, a car must be insured, taxed and have an MOT to be driven on the road. The penalty for driving a car without an MOT is a fine.The most relevant exception to this is if you are driving your vehicle to and from a pre-arranged appointment for an MOT and you must take a direct route to the garage (but the vehicle must be insured). Although you must be aware that most failures of MOTs are offences in their own right so you may be committing other offences, for example defective tyres, brakes, lights, steering, horns etc.However if you are stopped by the police on the way to or from the garage the onus is on you to prove that you had a pre-arranged appointment. Where possible it is always advisable to book your car in for an MOT in good time.There are one or two other very minor exceptions in addition to the above but they do not really apply to the ordinary car driver.  Hope this helps 

Stopping off at your Mums overnight isn't 'driving direct' to the MOT - you could leave the car at the test station on the Sunday, and get a taxi to your Mum's Alternatively - can you tax it online and get the disc sent to a UK address?

Tax it online before the MOT expires and book an  MOT, you will be fine. tax discs are going soon anyway.

Oh and nice to hear from you too.