After briefly wavered by our accountant friend here, I realised fundamentally there's nothing wrong with my strategy as it works and profitable for equities. The difference between equities SB and forex SB is the impact of volatility. So, I am going to move my strategy development and experimentation off SB to Oanda where I can control the the effect of volatility. As they allow trade value of as low as $1 per trade (ie, along the lines of $0.000001 per pip), the danger of volatility can be reduced to the exact level I want, which would be higher than equities, but lower than SB'ing £0.50 per pip. In my view the typical background noise level in forex renders trading £0.50 a pip impractical for my strategy that relies on position accumulation through pruning instead of precision entry. Now I see why there is a minimum bet on SB - these bookies are rather devious !
I can say to our sucker fish chum: no, you have not been to where I am going, or you would have seen the profit potential as I do with my equities.