Don't expect any sense from Anglian water, they can be deaf to complaints. The government said no one can be forced to have a meter fitted, so you need to find the appropriate legislation on google and be ready to quote the bit that concerns your situation. At the moment the water companies are running without competition ( unlike the gas, electric, phone etc) so you have no choice but to use Anglian, so they think they can walk all over the customers. You may be better posting this in the " law" section, some good lads there,know all the stuff.
Alf.