I know this is an old thread but for anyone coming across it:
I've made this cake every year for a long time now and never have problems. I have made a couple of changes though.
I don't use glace cherries.
I don't always add all the egg. I try, but when it starts curdling, I stop. Sometimes there's as much as one egg left that I don't add - that's okay. The main thing is to really beat it well. It takes a good half an hour to do all the mixing but if it's not done thoroughly the cake won't rise, which means it's more likely to overcook.
I wrap cardboard (from old cardboard boxes) around the edge of the tin, coming up an inch or two higher than the top of the tin. I tie it with butcher's string to hold it in place. (I use one layer of baking parchment with the hole cut in.)
It does take less time than she says, but definitely longer than 4 hours. Once 4 hours is up I find it's fine to keep testing it - and around that time I remove the top paper with the hole.
I have a fan assisted oven, so I set it 10 degrees lower than the recipe says. I've done it in several different ovens over the years and it always comes out great. The only time I've ever had trouble was when I was living in Western America - there, the ovens are a lot bigger, it was 3000 feet above sea level, and the climate was very dry - I don't know which of these factors were actually contributing, but the result was I had to halve the baking time to 2 - 21/2 hours. Once I did that, easy.
Persevere! It's way better than a store bought cake.