Hello there,
Regatding flights from the North I may be able to help a bit here
During the summer Balklan fly from Newcastle to Varna, often via Doncaster.
We are using this flight line on Saturday.
It isn't the cheapest, but Manchester is miles away for us, we live in Northumberland.
To Varna, then Ruse and to the house in Gorsko Ablanovo
Hope this helps.
David Hall