In short, almost all forms of gambling are permitted for those of 18 years and over, and some forms of gambling (lotteries and some small prize amusement machines) are even permitted for those over 16.
There are several reasons why bet365 accounts can be restricted, including matched betting, unreasonable betting behaviour, GamStop (self-exclusion), and exploitation of bonuses.
Any negative balance on your Account will become immediately due and payable to us, and your Account will not be closed until the relevant amount owed to us is paid in full.