trop, din007,
Cornhill cannot prevent you from trading, (unless there is a lock in period) but they can try and pursuade you not to sell, as they did with my FMGL.
I rang twice to sell, and the dealer asked why I wanted to sell, and then informed me "there's buyers in the market" and "news expected soon" type of comments. It was a battle of wills that I didn't like, as he twice pursuaded me to change my mind, when I really wanted to sell.
The third time I simply told him I wanted to sell, to cover a tax bill, and my order was finally executed.
A couple of day slater the price dopped, and has been dropping since!