Depends on your approach. If you trade manually based on market sentiments it may be essential to know ins and outs of the country which currency you trade. For example knowing UK political system well making correct interpretation of current Brexit battle can give you an edge as the story spins out and so you can show consistently good performance trading Pound.
Normally CHF currency has lower volatility so pairing it with other currencies may give you a flat low volatile currency pair. In that case EURCHF and CHFJPY are low volatility. EUR and GBP have history of correlation and it’s still a good haven for scalper strategies and swing trading. Some other pairs like NZDUSD and AUDCAD and AUDCHF also have low price movements and are good for strategies that don’t need highly movable market to be working.
what to do with gbp and eur pairs......this shows u dont have any trading plan or u didnt checked urself how ur system is performing on this pair. pls make a plan first and then chk any pairs, u need to make efforts to find out things which works for you. do not rely on people