The Islamic Centre in Liverpool prays according to the Shafi'i Asr time, too. I rarely go for jama'ah (I hope to start going to the mosque more often this year, insha'Allah) but I tend to vary it. If I know I'm going to be out at, say, 2:10pm when it is the start of Shafi'i Asr, I will pray Dhuhr "early". I mostly follow Hanafi timings unless I go to the mosque, but to be honest, it depends on my schedule. If I'm in class or something at, say, 2:10pm, I will pray Asr based on Hanafi rulings instead. But if I attend jama'ah at the mosque, I will pray Dhuhr earlier and follow Shafi'i times, so I can pray with the congregation. Both timings are correct according to scholars, so I guess it doesn't really matter which one you choose. On my prayer sheet I have the standard rulings and then write down the Hanafi time in brackets underneath it, so I don't get confused.