Yes, you can. It's a free country, you can do (almost) anything you want. Bankers can f**k around and bring the whole system down, and the public can then go and protest by smashing in the banks windows...murderers who get life for what they done can get out only a quarter of the way through their sentence, and immigrants can come into the country and get paid free money from the taxpayers purse.
So, WHY would they "ban" you from doing a second degree?
You can do anything you want! THIS IS ENGLAND!