Well, that's pretty weird... you could try posting about it in the UK forum to see if anyone else has this problem. (For one thing, I think the UK mods check the forum more often than ours check here.) If UK1 is the only place where you're having that problem, it seems like there must be something different about your settings for UK1, or it's not something on your end at all. You'd probably still get a faster response if you filed a support ticket, however.
About the easter missions - the benefit is that they refresh all the missions in all the zones. The only other time you get a refresh like that is when you level up, and since I'm a soft cap player, that doesn't happen very often, so I quickly run out of good missions to do. If you have the easter missions around to refresh all your missions, you get a fresh batch of hard missions with great coin and exp. As soon as you've used those up you can do another easter mission to get more, thereby optimising your income. To provide some statistics, on a good day without any holiday missions, I make about 3788 coin and 414 exp per energy (total for the day: 1,136,313 coin and 124,319 exp) . On my best day with the easter missions, I made 5031 coin and 541 exp per energy (total for the day: 1,509,421 coin and 162,592 exp). It's a very big difference. If you're serious about making the most coin and exp you possibly can, holiday missions are invaluable