Assuming the tamper circuit is connected correctly then id say its a faulty bell.
If the tamper circuit isnt then id say you either a faulty switch or it needs adjusting
its not compulsory, doubt it will be but insurers shouldn't request band names etc, ie they shouldn't request a redcare. So they created lps1277 so they don't have to test all the devices that are out there. But the webway meets lps