If you use Halifax as your broker you presumably deal in uk/european stock in the main. If this is so you could use com.direct who I find quite good. There is no annual charge and there is no charge for a stop loss or for stop buys, sell limits or buy limits for that matter. There is currently an offer of £50 if you join with a current account holder (mind you the account holder also gates £50 ! )
Commision is £12.50 whatever the deal.