I tend to use Aquatic Magic all the time as they stock what I want and they always seem to be good quality.
If you take standard delivery they will remove all leaves because they will die in the tank anyway and then after they will grow back even better.
If you order in bulk then they suggest express delivery and leave the leaves on.
I also get some Tropica plants from P@H but only if it is within a day or so of them being delivered in as they dont have a clue about plants and they tend to take some bringing back to life.
There is a Maidenhead Aquatics just outside of my town which has some nice cascades of plants although I havent bought anything there yet.
Andy