Hello. Another vote for Aigle. Here's why. Sorry for the long post. My first Glasto was 2016. Second day in my newish cheap wellies split. Luckily I had over packed and also had walking boots and gaitors. They did the job until Sunday, when the mud ripped the sole of my walking boot (mind they were old). So it was back into wellies, tapped up with Gaffer tape.
The advantage of walking boots, is the grip. In wellies, I slipped everywhere but taking walking boots off, you get your hands filthy.
When I got home, I researched wellies, even going on horse forums, as these people live in wellies. Hence I found Aigle. The Aigle is a shapped wellie with a walking boot sole. I often do 6 miles a day in woods walking my dog. They are expensive but worth it. Can walk for miles in them. But don't get the ones with the neoprene lining, your feet will melt.