Thinking about a winter trickle charger to keep battery OK. Any suggestions for an inexpensive one which functions? Thanks.

Ctek are widely recommended. I've had mine for getting on for 10 years. I think some of the German car makers sell Ctek chargers with their own branding on.

 

https://www.ctek.com/products

Clockworks, Thanks for your suggestion, however while visiting Aldi I have found one of theirs @ £12.99 which looks as if it will do perfectly well for trickle charge in cold weather should it be too inclement for me to drive. Time will tell . . .