Just thought I would give some updates.
I returned from my trip to WDW with these tickets. I had used the chat feature on
mde as well as calling tickets and both said I could not update the UK tickets to annual passes. I went to MK town hall guest services on day one to see if I indeed could update and it was a simple yes! The amount I was charged was approx $730 plus tax. I have a grad trip for my daughter coming up in the spring and we tend to do 10-day trips so it was worthwhile to me.
Now fair warning, I did do my upgrade on day 1 as I wanted to get the food and merchandise discounts. But. I did lose the extra pluses of water park, miniput etc, and I lost the photopass. We did get the few downloads we had done before visiting guest services. We weren’t really going to be using those extras. You can add a Water park and photo pass feature to your annual pass with Additional costs. I’m not sure if one was to update to an annual pass at the end of your trip whether you had to pay for the water park add-on since they back date your annual pass to first day tickets are used.

I was worried that if I waited later in the week, I might get a cm who said I couldn’t do the update.
Also, we picked up the bands at Planet Hollywood on our Disney springs day. They were the older battery, plain blue teal ones. They are given without activation. We had new bands purchased with the resort, so we decided to keep these for a trip when my DDs bring their boyfriends who don’t have bands. The teal was a pretty colour.
I didn’t use the extra offsite dollar drink and coupons that came with the uk deal, so can’t give any insight into those.