Return address of next value in list which doesn't match criteria

Evening all - hope someone can help me with another head-scratcher!

Book2.xlsx


I want to sum the numbers in colB for each of the headings (the yellow cells). So the first sum would be of B1:B7, the next B9:B11 etc. I need this formula to automatically work out for itself the correct range to sum for each heading though, as the headings and number of corresponding fields underneath may vary. All fields will all start 'UK' though - that is the only constant.

I started working on making a formula to find the next row down that did not contain 'UK', and create a range based on that, but I just couldn't get it to work...

Hoping I've explained myself well enough for someone to help!

Thanks in advance