Can anyone name this font? It looks like Gill Sans but the "a" is different.
Thanks in advance.

It is Gill Sans. What's different about the 'a'?

I'm using Gill Sans MT. The lower case "a" is different and the r and e look different too.

I can't speak to that, as only you know what you're looking at.

Your sample seems to match the Gill Sans seen here:
https://www.myfonts.com/fonts/mti/gill-sans/

On the sample, i'd say the end of the tail of the 'a' goes down, whereas in Gill Sans it goes up.
But image quality is pretty low, it's hard to be sure.