Samsung Galaxy Tab — It seems Google Play Services has gone haywire.....

Galaxy Tab 8.9 GT P7300 Android 4.0.4 ICS

About a month ago, YouTube closed itself unexpectedly and the display reverted to Desktop. Unable to restart YouTube. Tried Gmail, which would not download any new emails, and then closed itself. Google Maps constantly showed a popup "Waiting for location". Spent 24hrs trying to fathom out the problem, but no luck, so took the tablet to the local Samsung office. The technician there seemed equally puzzled and could only suggest a "Factory reset option - don't forget to back up all your files." Carried out the Reset, and Gmail/Maps/Youtube all work now as factory installed versions, ie. Youtube looks really different and does not offer historic use preferences etc. and shows "A newer version is available". If I select the newer version the problem starts all over again. I get Notifications of "Updates available" which seem to be mostly for Google apps (Google+ / Hangouts / Gmail etc.) If I update Gmail, (don't use the other two), the problem re-occurs (no new emails etc)

Current Gmail ver is 4.1.2 / YouTube ver is 4.0.23 / Maps 8.4.1

Tried looking at "Settings / Applications / Running" and Google Play Services, which is ver 10.2.98, has 3 entries, varying from 0 to 2 processes, and from 1 to 7 services, and is constantly restarting itself after running for only between 5 and 15 seconds. All other "running" apps appear to have run since the tablet was restarted, i.e several hours. I have checked on APKMirror.com, and see that Google Play Services Ver. 10.2.98 was only available from 13 February and that was about when the problem started. I did not update it then, but maybe it auto-updated (can it do that?) I have downloaded/installed Google play services apk 10.2.97 which seemed to install OK, to try and backdate the current file, but when I then updated YouTube, the problem re-occurred (instant reversion to Desktop)

Any ideas please?