Hi,
Will going to a shop wont help alot except seeing the dimension of the monitor only and if the monitor is playing a movie or something so good, still does not mean it is good. For example, I bought a BenQ monitor from Amazon and when I got it and ran Eclipse the colors where away off to my laptop and other pc monitor so I returned it and got another one (BenQ gaming monitor).
So what I suggest is, see reviews and unboxing videos on youtube. When you like one and you think you can find it in London ask here for feedback and help. This can guarantee to get something better and will meet your needs.
Regards,