I found a card that adds a % rather than fixed amount for foreign transactions and this is working well with Didi. The WeChat wallet is activated as soon as you receive and open a Red Envelope - ie as soon as someone sends you money. I have linked UK cards to WeChat but what is the point of doing this when it's not possible to transfer funds?

Also is it possible to choose the Didi destination on the map? The way I do it now is a little laborious - I find the destination, remember the name, then type in the name.