For those who like to use custom DNS servers rather than the TalkTalk ones, this may be of interest.
I've benchmarked a list of all the public ones I could find using a tool called DNS Bench from https://www.grc.com/dns/benchmark.htm
Note that if you use non TalkTalk DNS servers things like HomeSafe will break, but some people might see this as a good thing 😉
Fastest servers for me are at the top of the attached list. It's a large graphic so you may need to zoom in 400% to see them. Feel free to benchmark them yourself as your results may vary.