The same thing that you have already advised me about, viz
There was a problem with the webpage and it is being reloaded.
Initially, the reset seemed to have cured it', but not for long, so I deleted a large number of apps with no better result, and then I installed Google Chrome, which is fine. Incidentally, the app said GET on it which I assumed meant that it was free, but there has been a £1.59 charge posted to my credit card which I hope is a one-off.
I have been reading posts on other forums and a number of people are finding that while IOS9 and safari work OK on their iPhones, they seem to be having the same trouble with iPad that I have described.