Upgrading from WT+ to CW miles required?
I've had a search but I can't find the answer to my question and thought I would ask here before phoning up.
Next week I'm flying to Taiwan from Glasgow for a few days and I'd like to upgrade the London -> Hong Kong part of the trip from WT+ to CW.
I've not used my miles for ugrading flights before so keen to have answers to the following:
How many miles do I need to use to do this? Can I do it one way or does it have to be return?