Hi James,
Apologies for the tardy reply and thank you so much for taking the time to help me.
I got it sorted - the issue was with my spam comments - although I have a plugin to catch the nasty so and so's - I had not taken the time to clear the spam folder so it was taking up a silly amount of space.
I haven't tried what you advised above but if I come across an issue in the future I will give it a go.
Thanks again,
Edwina