Marine Refrigeration Module/Courses?

[Thaumaturge]

I would like to develop my engineering knowledge and competence to encompass (leisure craft) marine refrigeration systems, can anybody please point me towards any relevant short courses or distance learning organisations that offer them?

My particular emphasis would be on the troubleshooting, maintenance, charging and repair elements. I will be back in Blighty during November and early December.

Thanks in anticipation,

Vince