I bought a second hand tank from ebay last year and it came with a fluval 204 external filter. I have been really happy with it. You would need a bigger output for your tank - I was told roughly double the size of tank for filtration. My tank is 130L. So you could think about the fluval series - the old ones end in a "4" ie 204, 304, 404 or the new models are now the "5" series. Don't know whether you would need the 304/5 or the 404/5 - someone with more experience could tell you that. It's always worth having a few options when searching on ebay isn't it!
I've been doing some more research and now have my eye on an Eheim Classic 2217 which looks ideal as I've read nothing but good things about this filter and it looks like it could also be suitable for a bigger tank should I upgrade in the future, so it has a "future proof" element to it too.
If anyone uses an Eheim 2217 and can let me know their experiences of this filter, good or bad then I would obviously be very grateful.
Thanks for the extra info Diadeb20, the Fluval's look good too, if I was going to go for one of those then I reckon a 404 would be best as that's rated for tanks at 400l.