It sounds like those Drafts aren't at Gmail and exist on your iPad only. I'm wondering if you had deleted your Gmail account and then added a different Gmail account if they would have re-appeared.
This Gmail account is your only email account on the iPad?
Hi Brian.
Sorted at last.
On my iMac, I opened Mail and chose Preferences and from them I chose my Gmail account. I opened the "Mailbox behaviours" tab and the Trash setting was saying "Gmail/Bin" so I altered it to say "Trash" and came out (which auto saves).
Then I opened Google and I went into my Google account and opened Gmail. I clicked on "Drafts" in the left hand column and got 3 pages worth of emails with drafts associated with them. I selected them all, page by page, and did a right click on one of them which gave me some options including "Delete drafts", which I did and eventually cleared all three pages.
Then I opened Settings on my iPad Air, selected "Mail', then navigated to my gmail account and deleted it. (It only deletes the account from the iPad - not the entire Gmail server's worth). Then I clicked "Add account" and chose Google, calling for my gmail address and password in the process, everything else being automatic. Then I powered down the iPad and restarted it.
I opened Mail and checked and all the saved drafts no longer show up in my main Inbox. I shall know in a day or two whether the problem is entirely cleared, bur at least I now know what to do even if they reappear in the future.
This has been a long investigation but I hope it will help others to overcome the problem of draft emails showing up in the Inbox, and I thank you, Brian, for your patience and assistance.