It's got a different progesterone in it, and they have doubled your dose of oestrogen.
They switch me so often I've tried all the ones you mention and I found the oestrogen part of Evorel Conti patches identical feeling to the Estradot patches at the 50 dose, they both worked for me and they both contain the same estradiol hemihydrate which someone else commented absorbs better than estradiol that isn't hemihydrate, but I'm no chemist, I'll take their word for it!
Your GP probably wanted you on the continuous dose of provera. When I was on a 50 patch (Evorel conti are this strength), I had the choice to take either 5mg provera every day or 10mg for 12 days a month. I opted for the 10mg dose for 12 days and felt deathly ill, I took four days off work sick and I could barely move off the sofa in that time, I slept around the clock as well as feeling like I'd a proper bad flu.
I'm guessing you didn't get on with provera either?
The northisterone is a better one imo, didn't make me feel ill like that, but I prefer utrogestan over both, because after 2 or 3 months Evorel Conti was making me feel depressed and I can safely guess it was the northisterone, it does that to 10%-20% of women, so don't worry if it does it to you as well, there are alternatives and for most women it's ok.
Which progesterone suits you is very individual but normally a clear yes or no from each woman for each progesterone type. One day they will find the mechanism behind the tolerance of one over another, for now it's trial and error and nothing more.