Thank you very much everyone for sound tips.
I am intending to day trade (about 50 bets per day), not sure if it is classed as scalping as I won't be in and out in seconds or minutes but more like anything from 5 mins to 20 mins. I guess that's called short term trading? Just looking to make £10-£50 profits per bet.
I am not particularly looking to trade as Hoggums described above but I will be trading throughout the day so if it happens or as and when it happens, if SB is quoting late for whatever reasons, it's no my fault and I'd take my profit if it's there regardless.
SB market may not be mature yet but I bet brokers must be thinking there will always be newbies.
I won't moan for unfilled orders. It seems to happen quite a lot across the board so looks like I'll have to bear with it.