Another iPad question, uuuuurgh

Hello

I noticed this morning that the storage on my iPad used by my single little yahoo mail account that I regularly clear out is 750MB!!!
Outrageous I know!
Now, I have scoured the internet to find an answer, the two options I was given were:
Manually remove emails, i do that regularly as i said
OR
Delete mail account, people say that fixes it!

So, I deleted my mail account, and now, its 10MB more than before!

Therefore, i decided to come on here and ask all you clever people, what can I do?!
I am beginning to come to the conclusion that all the mail stuff, including contacts and calendars etc. comes under "Mail" in storage?

Please help me :) :(