Well, it depends.... I mean, first of all, where do you wanna opening your restaurant: In London or other cities? ; In China Town or local area
In China Town, you may expect that there are many restaurants which have provided various dishes already. Most dishes you provide overlap
other's menus. It sounds frustrated, but it's true. In local area, you might concider about take away
In my opinion, I recommend you open a restaurant with home-made
dishes rather than general one. Actually, what I eat in the China Town, the taste, well, is not so bad but not delicious enough. Another suggestion is high quality of service, of course, like what LennyeTran said the waiters/waitress can speak in fluent English. Nevertheless, you need provide a dicent atmosphere for enjoying food.
I'm superised that in Manchester China Town, the Tai food is more popular than Chinese food. Local people are willing to pay more in the Tai restaurants
. In my opinion, price is not the issue. The taste and service are main factors.
If you focus on Chinese customers, that's all right. I think you may be good at it. However, if you wanna attracting western customers, you need to go to local restaurants, e.g. Italian and Tai one in order to understand their practices of food and drink
Above all, I hope it helps, finger cross.