I would agree with Big Chris. The 2400 will be superior to 800/820.
There are quite a few excellent players in the market for your budget:
1) Pioneer BDP-320: £349
Renowned for its superb PQ & AQ (maybe the best for your budget), but slightly slow to load.
2) Pioneer BDP-120: £269
Basic player with Pioneer quality. again slow to load.
3) Panasonic DMP-BD80: £280
Panasonic players are good all rounders. Excellent PQ & AQ (almost as good as the Pioneer), better loading times, plus you can access youtube & picasa.
4) Panasonic DMP-BD60: £199
The only difference between BD60 & BD80 is that BD80 has analogue output as well. You won't need this feature, because your receiver has HDMI. Panasonic claims that BD80 has better components, but in real life, there's no difference in the quality. I own a BD60 & am very happy with it.
5) Sony S360: £199
Fast loading time. Excellent PQ & AQ. Some people don't like the absence of eject button on the remote, although you still have to get off the couch to remove the disc from the tray! but if you have a universal remote like Logitech Harmony, you can eject with the remote.
6) PS3: £289
PS3 offers a lot more than a blu-ray player. It's a game console, a wireless media player which can play songs & movies wirelessly straight from your PC to play on your sound system, & view pictures from your PC wirelessly. You can also access the internet & watch youtube etc. (you can access any website).
Even as a blu-ray player, it's excellent. It has the fastest loading time, still unsurpassed. It was my main blu-ray player until last week. The only reason I went for the BD60 was because I wanted a player which can play multiregion DVDs & PS3 cannot be multiregioned. I'm still trying hard to convince myself that BD60 is better than PS3 in audio quality (not convinced so far). Picture quality is on par with the best players in the market.
Even Samsung & LG players are supposed to be very good & have very fast loading times. I don't have much experience about them, so can't comment.
IMHO, buy a basic blu-ray player for £199 & spend the rest of the money on buying a better receiver.
Hope this helps.