Thanks Gordon. I think it is me, well my server address, which is maybe triggering some sort of protection. When I attempted access by phone, using the phone network rather than WiFi, I was able to open PlaymoDB pages without problem. Now I am using a proxy server and my tablet is linking fine. Frustrating, but probably a sign of the popularity of PlaymoDB if Heather has had to protect it in this way- legitimate users get caught up the same way as inconsiderate users.
And I am still getting the message '403 Forbidden Sorry, page forbidden OR timed out. If you can normally access this page, please try again later' even on the proxy server. For example, when I search for 'rotor' from the homepage, I get results, but if I search for 'tail rotor' I consistently get the 403 Forbidden message. But 'helicopter tail rotor' works fine, so it's nothing to do with the length of the search string! Something strange going on there!
So I think there are two problems, access to the website being blocked and the 403 error message thing.