Have been having a window opening regularly as I browse, advising that my storage limit is approaching and asking me to go to settings to manage it. Not sure what I 'm supposed to do, most of the list has apps as the main user-up of the MBs, but the only recourse appears to be to "delete app " which I don't want to do. Or should I do so and then reinstall the app? Would that be effective? Any info much appreciated.

For a quick fix, you can try this:
Battery Doctor - Must-have Battery Management App by KS Mobile, Inc.
https://appsto.re/gb/gRZTK.i

You need to look at the Storage statistics in Settings, as it's not just the size of the app but it's associated data. For example, I've seen iPlayer have nearly 1GB of data.

Thank you, bit surprised about the "battery." reference, was unaware that it had anything to do with the issue of storage capacity.
The listed apps show the MBs used; as I said in the op, the only way to 'clear' the stored stuff would seem to be to delete the app, and reinstall if desired, some time later. I assume that the more one uses a particular app, the more MBs are used, thus using up capacity?

The battery tool has a memory and storage utility too.

Yes, if you delete an app it deletes all associated data, but you can reinstall afterwards. You obviously need to make sure you don't need the data: game saves etc.

Or you could just delete the data associated with each app.

Thanks again, for both replies, very helpful; just can't see how I can "delete the data associated with each app " - there isn't an obvious avenue to do this as far as I can see- perhaps you could specify the necessary method in detail-?

I don't think there is a method of deleting the data associated with an app unless the app itself supports it. Taking iPlayer as an example; you can delete downloaded programs within the app, but not the 1GB of other data associated with it. The easiest option is to delete the app and reinstall.

Sorry, my fault, I was thinking of my Android phone, where I can do this.

You can remove things like history and cookies by Settings/Safari/Clear History and Website Data.

Doeas the message refer to the physical memory on the iPad or the virtual memory in the Cloud?

h

Not sure: will see if I can ascertain when the message next appears,, assuming that there's an indication at all...

Good point. You tend to see 'storage full' messages about the 5GB limit for free iCloud storage long before the device itself runs out of storage.

The iCloud storage still has 4.6 available out of the 5GB.