Oh! I would suggest to take a good look at that.
Is the commission £0.66 per 10k? If so then the commission converts to 1 pip (divide 0.66 by 1/1.495 where 1.495 is the GBPUSD rate) - meaning that your total transaction cost is 0.8 spread + 1.0 commission = 1.8 pips total.
If your spread is 1.8 pips then I think it might be quite difficult to become profitable scalping because you are down 1.8 pips from the word 'go' every time. Even if the 0.66 is in dollars rather than pounds, your cost is still 1.5-1.6 pips.
For comparison, my spread is 0.3 with commission of £0.6 - thus equating to 1.1 pips. I generally don't have targets/stops of less than 15-20 pips in eurusd - though I am not a scalper.
Perhaps other some scalping T2W members will chip in and give you their comparative transaction costs.