> completely reasonable
This is a personal decision to be made by the data "donor".
The NHS website cookie banner (which does have a correct implementation in that the "no consent" button is of equal prominence to the "mi data es su data" button) says:
> We'd also like to use analytics cookies. These collect feedback and send information about how our site is used to services called Adobe Analytics, Adobe Target, Qualtrics Feedback and Google Analytics. We use this information to improve our site.
In my opinion, it is not, as described, "completely reasonable" to consider such data hand-off to third parties as implicitly consented to. I may trust the NHS but I may not trust their partners.
If the data collected is strictly required for the delivery of the service and is used only for that purpose and destroyed when the purpose is fulfilled (say, login session management), you don't need a banner.
The NHS website is in a slightly tricky position, because I genuinely think they will be trying to use the data for site and service improvement, at least for now, and they hopefully have done their homework to make sure Adobe, say, are also not misusing the data. Do I think the same from, say, the Daily Mail website? Absolutely not, they'll be selling every scrap of data before the TCP connection even closes to anyone paying. Now, I may know the Daily Mail is a wretched hive of villainy and can just not go there, but I do not know about every website I visit. Sadly the scumbags are why no-one gets nice things.