You have to develop a good trading strategy and trust it. It's best to become apathetic about shorterm results, as caring about losing trades or setting daily loss limits will negatively affect your trading. Unforunately, most of us only become apathetic about it through large losses. We learn more from our defeats than from our victories, at least for those who are able to learn!
The problem is, until you have attained your "big win" and the starting balance has increased from £5000 to £6000, you don't know how you are going to think or react until you actually get to that stage. Therefore, assuming that the "big win" will release your emotional turbulence ahead of actually experiencing that situation is nothing more than unsubstantiated speculation. You cannot escape from the fact that even though you are trading with a £1000 cushion, this money is now YOUR money residing in YOUR account. Once you actually get there, your trading style may change and you may become "protective", meaning that you take fewer trades, or close out winning trades with a very small profit in order to "protect" what you have won. This leads to you having to find 5 successful trades for every losing trade (depending upon your stop placement for the losing trade). Trading becomes difficult... The other side of the equation is that you may become reckless, and decide to hold losing trades longer than you "normally" would, because your thought processes are operating out of the "Its not my money so i don't care" mode. The reckless approach is the ultimate state of denial and will provide your emotional turbulence with the fuel that is needed to inhibit progess. So we can see that the "big win" creates new psychological questions that require a resolution, and therefore we can arrive at the conclusion that there is no escape from the emotional turmoil until you have addressed these issues directly within yourself.