Lebara roaming - multiple countries

Mason

Can anyone help?  Next month I'll be travelling to multiple countries for about 3 days per country.  These include Uzbekistan, South Korea, China and Vietnam.  None of these countries come within the "roam like home" offers provided by Lebara.  Lebara do offer Roaming add-on.  For example, 1 GB of data is £20 for 8 days if I select Uzbekistan as the country I travel to.  China is £5 for 8 days.

As I will be in Uzbekistan for 4 days and China for 3 days is it possible to pay the Uzbek roaming fee (£20) and then use anything I have left in China? 

I think this is unlikely but it does seem a bit steep having to purchase roaming add-ons for each country I visit.  Or, of course, not use my phone but given I'll be off the beaten track I suspect I'll need it when I inevitably get lost.

Any other advice to this old man that has little clue how networks operate would be welcome.

Thanks for reading.