During this lock down its impossible to get Light Bulbs from the shop, and it seems like amazon all sold out too! So, I popped the top off and saw that 2 LED's had blown (You can tell by the small black spot usually in the middle of the yellow part)
So, I removed the old LED's with a soldering iron, and replaced them with a 100 ohm resistor. Not because its the right value, but they were in easy reach and should prevent too much current going to the other LED's and thus more blowing. Really I should have calculated it properly and may have come out with a higher value needed.
Put it all back together, and there we go, All working again. I remember this bulb was nearly 10 Euro, as it was one of the brightest and apparently longest lasting so a good saving by fixing, but probably it would have been just as good to buy the cheapest, the insides seem the same.