So I got there in the end! Hooray!
For anyone else trying to implement, do follow @jimpower s instructions, but you do need to read down into the threads to find the adjustments, and also track down the instructions about where to put your .css and icons (that was a new to me). See here: Custom animated weather card for Lovelace
It was straight forward to use my xiaomi sensors where I wanted to.
Thanks heaps @jimpower & @DavidFW1960
