MATCH Function across multiple sheets

Hi,

I have been trying to use a MATCH function across multiple sheets so that I can pull information into a summary sheet. What I cant figure out is how to make part of the MATCH function dynamic so that it links to a drop down box with the names of the different sheets. Its a little bit difficult to explain in words so I've attached an spreadsheet that hopefully makes it clearer.
I have been trying to use an INDIRECT function with the MATCH function but I cannot get it to work.

I appreciate any help you can give me.

Thanks!