Do you request many full manuscripts? You wrote that you requested zero and rejected one.
Here's my question: When looking for an agent should you ony look in the country you live in or look one in which your current manuscript is based? My current WIP is a MG historical fiction about children who were evacuees during WWII in England.
I actually do not request many full manuscripts. If I like a query, then I request a sample chapter and a synopsis. I can usually tell from that amount of material if the author has real skill, and then I request the full manuscript.
As for your agent, you agent should not be based on where the book is set (how many Vietnam War novels are repped by Vietnamese agents to US publishers?), but should be based on where you want the book published, keeping in mind that very few authors have more than one primary agent.
If you get a US agent, that agent will most likely represent you around the world, either directly or via a network of sub- or co-agents. There are some authors who have both a primary US and a primary UK agent, but they are few in number.