My URL's suddenly appended with strings like /?v=560e51228bc1

Hi there,
This is my first ticket so apologies if I don't explain it very well! I have noticed that all my URL's are appended with something like /?v=560e51228bc1, for example when I go to my homepage which should be, I get instead. Have you seen this before and can you help me identify what is causing it please? I recently added to my .htaccess to enable browser caching as well as to compress my site. I added the following:

<ifModule mod_gzip.c>
mod_gzip_on Yes
mod_gzip_dechunk Yes
mod_gzip_item_include file .(html?|txt|css|js|php|pl)$
mod_gzip_item_include handler ^cgi-script$
mod_gzip_item_include mime ^text/.*
mod_gzip_item_include mime ^application/x-javascript.*
mod_gzip_item_exclude mime ^image/.*
mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*

<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access 1 month”
ExpiresByType image/jpeg "access 1 month”
ExpiresByType image/gif "access 1 month”
ExpiresByType image/png "access 1 month”
ExpiresByType text/css "access 1 month"
ExpiresByType text/html "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresByType image/x-icon "access 1 month”
ExpiresDefault "access 1 month"

Removing the code for those made no difference, the URL's were still showing, so I left them in (for your info).
I have lots of plugins installed and really don't know where to start troubleshooting.
Can you help please?