50 years after the last update the relevant portion of the map looks like:
I spent the first two decades securing what was left of Wales and Brittany. I tried getting an invasion of England, but the HRE's vassal Pope was having none of it, so the English remained a threat and could beat me rather easily. When they were off fighting elsewhere, I grabbed de jure counties. They always ended up taking them back as soon as they weren't distracted. However, that kept them from taking more land from me, which they would have done as their vassals were busy fabricating claims.
In 1150, it appeared that things were about to get scary as the King of England pressed his claim for Aquitaine and won it. I turned my attention to France in the hopes that I could gain enough territory there to even out the numbers game with England a bit. I also moved my capital to Wales and converted to Welsh culture. That allowed me to pump out a bunch of cheap longbow retinues, which also helped with the numbers game. Nonetheless, England could still muster about 10K more troops than me. However, they unexpectedly did not come after me right away. Instead, they pressed minor de jure claims against France and Navarra. It should only have been a matter of time before they turned their attention to me though.
And, then England made a huge mistake of the type that displayed such monumental stupidity only the CK2 AI is capable of making it. England attacked the HRE. An HRE that was at peace and had twice the total troops as England. The English armies were destroyed. All of them were dead in a couple of months. I quickly found a willing claimant to the Duchy of Wessex, landed him in Scotland and pressed his claim. The English surrendered after I had sieged only a single holding and no battles had been fought. I expected reprisals to come before too long, but while waiting for England to replenish its levies I went back to France and took some land there. Then, before England came after me, the Pope intervened and called a Crusade for Jerusalem. England cheerfully took his entire army off to die at the hands of the Fatimids. I waited patiently for my truce with them to run out. The day that it did, I declared war for some patsy's claim on the Duchy of Kent.
When the English came back from Crusade, they were a little bit upset with me. Despite only being at about a third of their total strength, they immediately declared war. I was busy fighting the French at the time, so I guess the AI thought it was worth a chance. I quickly wrapped up things in France and then returned to England to crush them. That's when the levee broke. The game says that the English king died a natural death, but I know he died a broken man, muttering about his own stupidity and raging about me. His gay son became the new king and immediately faced a revolt in Aquitaine. I decided it was a good time to take the Duchy of Hwicce. The English king decided to personally lead his troops in battle against me and was killed in battle. Another Duchy was mine. His brother took over and decided to attempt to revoke the titles of the Duke of York who had gone heretic. Unfortunately for the new king, I declared a holy war against York and beat him to the punch of the Duchy itself. York had a couple of other counties, England was able to eventually beat them but this new king died in battle fighting the heretics. This time, England got a boy king. A boy king, who quickly found himself at war with me for the Duchy of Mercia. I won.
While all this was going on, my realms had nothing but internal peace. My genius female queen reigned for 45 years. The tanistry electors replaced her with an 18-year-old strong lad married to a princess of the HRE. I'm currently in year seven of his reign. I'm still a few counties away from creating Britannia. I can currently usurp the kingdom of England if I want. I'm four counties away from usurping France. England just folded to an independence faction in Aquitaine too.
Long story, I know. TL;DR version: I've broken England and France. It's only a matter of time before I get those first two Empires.