That house has got a very flowery History
in the not so recent past, as I'm sure you're aware.
It looks like it is a "foremans" house as it also has the shield on it. The rest of the terrace may not have had a downstairs bay originally, quite a lot of terraced houses had them added on, I'm not sure, but I think there may have been grants available to put the bays on.
Cavendish street got bombed 3 times during WW2, one bomb area was the corner of Cavendish St and Old Bidston Rd. So there is a slight chance your house was damaged then and rebuilt.