First off...the stage version of this musical is not the same as the original 1980 movie many love except for the setting and theme. It doesn't have any of the songs from the 1980 movie version with the exception of the title song, sang at the end. This appears to be overlooked or misunderstood by some of the other reviewers. This musical stage version more closely follows the updated remake released 20 years after the original.
However...what they do have correct is how amateurish many of the singers and actors are for West End pros. 3 of the male leads seemingly were picked for their looks and not singing or acting ability. One was consistently flat with his over singing and the others over sang and acted. The characters were all caricatures, as it was written, not real people, and the accents problematic. This also makes the show feel very dated.
The musical stage version is not one that is remembered as being memorable to begin with and rides off the coattails of the popularity of the hit movie. This filmed performance from the West End proves that, and will be hard to get through for many musical theater fans like myself.