It would take too long to set up as its currently running on a testing server in-house. I have fixed the problem however.
I decided to set everything back to its initial state (default), found the lines of code within the wagmp_map_1 file that relate to the marker images and more importantly their image dimensions and altered things that way. It now works a treat, thanks.
Can I also suggest that in a further upgrade to the extension, that some of these features such as alternate image markers, default start zoom could be implemented in the initial settings panel? I am having to remember changes within a file that can be easily forgotten, if you don't use it that often or remember to make notes etc.
Also is there a way to alter the bubble graphic. Rather than rounded edges, have traditional square edges etc. etc.