'Harry may well have been right about it migrating from Lord Lovel to Barbara Allen, but I'm pretty certain equally it didn't start life with Lord Lovel.'

Don't at all think that is what he meant or implied, Steve. He just meant that HIS version of LdLvl contained those bits & HIS BarbAllen didnt, so he regarded appearance of the truluv-knot motif in the latter as WRONG, misguided, mistaken, due to confusion ["They get mixed up"]! The idea that there could have been renderings of B Allen in which it happened to fit correctly or appropriately didn't occur to him, lay outside his range of the possible or the acceptable.