Depends what you mean by hilly. I have one course that is constantly up and down and that is slower than my flat pace. Another course has two very steep climbs but then long downhill sections, this one is usually faster than my flat pace.
Is London genuinely so bad? I have never run it so have no opinion but there is a lot of anti VLM posts on the forum. I just wonder if it really is dreadful or if it is just people being too cool for school (bit like saying you hate the Beatles).
I hope to find out one day by running both a London and a smaller one.