Hi all,
A little extra to this. I've just tested my website speed on https://tools.pingdom.com and it is reading as significantly faster, same as on another speed load test site.
I do still need to speed up the images but maybe I've had everyone on a bit of a wild goose chase based on a reading from another site. I do know my images are too large because they don't load well on a mobile phone on 3G so that's my weekend work.
Still interested in the 'extra image' issue if anyone else suffers from it too.
Thanks for everyone's help.