My modified host file blocks most ads when I watch videos on sites like Hulu. I haven't tried it on ITV or CH-4. Try configuring your host file to block ad servers. Check here
for instructions. You can probably d/l the stream using flashget or a similar utility. Maybe you can get someone to write a script that'll d/l, convert it to xvid and store it on a server....I'd like to know how to as well.