Thanks for following up Kat

The second part is now working, ie if I click add services it brings up the panel with 'Royal Mail International Standard' etc and I can type in the box for example 'standard' and 'Standard Int'l Postage' appears as it should. 

The first part, if I go to revise an existing scheduled listing with defined international postage options it still looks the same as my first screenshot in the original post. 

However if I then refresh the page my existing international postage options reappear correctly. 

Or alternatively if I click 'Add services' the panel opens but at the same time I can see my existing international postage options appear on the page appear behind it and they are there to edit when I close the panel.

So basically it's not quite working, but is usable now with one of the two workarounds above.