Hi,
If you're not bothered by flicker, then I would go for the DL10, although having said that I would still take a look at the FX68 incase you find the 100hz picture appeals to you.
You might want to consider the Sony KV28CL10. This tv is exactly the same as the DL10, except it doesn't have a digital tuner, but this wouldn't be a problem as you could use it with your Nokia Freeview box. It can also be found for around the £400 mark.
I've used a 50hz Sony Wega for the last five years and have never had a single problem with it. I've been considering getting a new Sony 50hz for the spare room, so I would have no hesitation in recommending the DL/CL10. That said, there is also a very good range of 50hz sets available from JVC.
In general, the performance of 50hz tv's offered by the major manufacturers in the £400 to £500 range is consistantly good.