Update - Four months after handing over the obsolete iPad I can confirm it is still working well. I spend maybe thirty minutes a week checking the operation, searching and adding applications that are suitable for a seven year old (and are compatible with 5.1.1 - more below) and deleteing apps that are either not played/read or look boring, or turn out to be completed.
So far I have not had to pay for any additional services at all, plus the battery still functions for a good three days before recharging, though I don't check on how many hours this equates to.
Small issue is that there are only ten pages of apps that can be seen , which is the same as the later company iPad, can this be increased ? It's not a major problem since any app that are downloaded beyond the visible limit seem to be in the device, and appear as predecessors are relegated to the bin.
Quick hints for somebody owning one of these, but thought they were land refill material
1) When searching for content, keep the iPad in portrait mode so that the dates of release are visible, most compatible apps for iOS 5.1.1 are no later than 2014. Very little is available after mid 2015, though it is still worth time if looking for educational scripts and school homework apps.
2) User review stars help, but are not always a guide to better programmes.
3) When a good game or book is found, look for similar from the same designer to the left, the chances are they are also 5.1.1 compatible
4) Anything that has an update from a similar year to the app origin means the designer probably cares about criticism levelled at the app.
5) Avoid anything that is found with a search using 'kids' or 'children' in the line. Even selecting an appropriate age will cause all sorts of search errors.
6) Try some abstract searches, sometimes a common/popular game is in the system but will be called something different to avoid copyright issues.
Next, some of the games and educational apps found - and still being used four months later that make 5.1.1 still a useable system.