This probably is due to incentives - carrying a knife may bring a long prison sentence, carrying a bottle of acid or lye as weapon did not. UK changed sentencing guidelines last year.
Now, sure, especially in London. It's grown as a weapon of choice phenomenally quickly over the last 5 years, from almost nothing.
Seems like it may have been noticed being used for honour attacks in communities in London, Bradford, Leicester etc, and escalated from there. A particularly horrible form of attack.
