Changed to default Joomla template - rhuk_solarflare_ii - and tried madeyourweb also... but no luck!
They both do the same thing, stretching the icons...
Is there something in the code for the login module?
Thank you for your help so far.
Edit: I've noticed the icon on the login button itself always comes out the right size, it's just the buttons next to the inputs and links that are weird...