The data-set starts in 1995, and we can see a strong market from then right up to 2007, when there was a a synchronised fall of around 15-25% and thereafter an extended recovery which is now on pause.
Within this pattern there are other systematic influences where we see periods of price divergence (e.g. 1995-2002) followed by convergence or catchup (e.g. 2002-2006). In many parts we are currently in a period of convergence where lower-priced areas fairly uniformly outperform, however in London the reverse can be seen. Since mid-2019 the high-priced central areas typified by area WC have been the outperformers.