Richie, I think the reason for the confusion is I remember for a brief time another 'new' Cavern briefly being open on the opposite side of the street when the original got filled in after the building above was demolished (the Merseyrail ventilation shaft business).
There seems to be no mention of this on wiki or the official Cavern site.
There is however a mention of this other short lived 'new' Cavern on the opposite side of the street
here on the wayback machine.
In 1969 Roy Adams took over the management. Although he continued to provide a good standard of music and bringing in top acts together with a mix of top quality local musicians, the halcyon days of the Beatles and the Cavern had become fading memories.
Once the club closed in May 1973 and Roy Adams re-opened a new Cavern Club over the road the Cavern members and regulars moved elsewhere.As it happens, I knew
Adams older son back in those days (as the article mentions his younger brother Paul is involved these days with Gerrard in his Southport hotel venture). I remember at the time him talking about the closure quite well, the selling off of the signed bricks etc and him saying his Dad was moving the club to premises the other side of the road and that it had now opened. I lost contact with him shortly after this around early 74, as while he was a sound lad, very generous and a fervent Red, we moved in very different social and economic circles, so I never found out what then happened.
I suspect few went there, the original was not exactly popular by the time of the closure in '73, Annabels, She, Gullivers and places like that (I think Adams had an involvement in all them too) had taken over the club scene by the end of '73, it was all going disco while rock bands only wanted to play in larger venues like the Empire, Mountford Hall or the old Stadium. It wasn't until punk a couple of years later that live music (other than folk and chicken in a basket nightclub Eagles covers type bands) would profitably return to small venues.
I have no evidence, but I suspect
Erics then took over the defunct "new" Cavern premises in '76 and for some reason the short lived 'new' Cavern on the opposite side then became airbrushed out of history when in the 80's the new 'old' Cavern was reconstructed in the approximate original location and side of the street.
It's a strange one.
Edit:just noticed someone else pointing out this other short lived Cavern club on the opposite side of the street
here in the Cavern talk page on Wiki.
The Cavern club that exists now IS on the same site as the original. That is on the right as you walk up from North John Street. In the 1970's another club opened on the lefthand side calling itself The Cavern. The original club was not demolished due to the building of the Loop Line. The trains run much deeper. The building above was demolished and the cellars filled in with rubble. The original cellars were dug out and the arches rebuilt in the 1980's. The fake Cavern Club then called itself the Cavern Pub.