Since installing IOS9 on my iPad 2 the above fault notification has become more and more prevalent until now my tablet is completely unusable. To make this post, I had to switch on the PC - and that took a while, too.

Can anyone tell ,me what is wrong, and how do I go about re-installing IOS8, because I can't go on like this? My ISP on the tablet is safari.

You can't go back to iOS 8, sorry.
Your browser (not ISP) is Safari.

You could try resetting your iPad. Start with a reboot by holding down both the home button and the power button until the Apple logo appears.
If that doesn't work you could backup your iPad, reset it completely, then restore from backup.

Alternatively, try a different browser such as Chrome, or the new Adblock browser.

Hello Stig. I'm very grateful for your help and it is good that there are people like you on the forums who can help when stupid old gits like me can't get it right.

I tried your first suggestion and it seems to have cured the problem. Quite why I didn't think of this I don't know because it is my first plan of attack with anything electrical - PC, TV, PVR, Church photocopier, and especially the church organ!

Anyhow, thanks. I really am most grateful.

Ian J