@Mostropovich 

In the UK version, are you able to go to Settings > Chart of accounts > New and create a bank account there?  In the US version, this is where you are able to create a bank Clearing Account.  Then, you will be able to select that account in the adjustment account pull-down menu when entering the inventory quantity adjustments.  I suggest using a bank account type for the Clearing Account because a bank account is able to be used in various other areas of QB when you need the convenience of a clearing account (A/P, A/R, etc.).  However, if you're unable to set up a bank account type for the Clearing Account, the current asset account type will work fine for your inventory adjustments as per your screenshot.