It helps to understand what is going on:
The double ring is not a mistake and it is not a UK tone. It is the USA "distinctive ring" pattern for line 2 in a 2-line phone system, or a true distinctive ring service POTS phone number. By default, SP2 uses the distinctive ring #2 pattern for SP2. By changing it to use ring profile A, it will use the same ring tones as SP1.
If it isn't working, then you've made some other mistake, or your ancient telephone is not responding properly to the ring signal. Try a different telephone.