Mysql Nested sub query

Hi All

I need some help with a query in Mysql, which i would think that
a nested sub query would be required.
This is probably better understood with an example of what the output should
look like.
basically i need the query to run on a meter readings table and return
the last two readings in date order descending for each asset.

I hope that this makes sense

I hope i have attached the pics of the source data table and query ok.

Any assistance would be greatly appreciated

Attached Images