Assuming that the rules enumerated at that link are the complete rules, I have a Japanese bread knife that I use every day for its exquisite sharpness, and which would become forbidden by these rules.
The reason is that it has a 9-inch serrated blade, which is a very frequently encountered size for bread knives, and the angle at the tip of the blade is slightly smaller than the 90 degree angle mandated by the new rules.
The slightly acute blade tip is very handy when cutting some big hard vegetables, like water melons or pumpkins, or some very big breads, which have a diameter greater than the 9-inch blade length.
The rules as written on that site are ambiguous, because they could be also interpreted as only forbidding the 2-edged blades, where one edge is plain and one edge is serrated (a kind of knife that I have never seen). However this interpretation of the rules is contradicted by "other than a serrated cutting edge of up to two inches next to the handle", which is a typical feature of single-edged blades and which would not make sense on a 2-edged blade.
The rules still allow the possession of a fighting/utility knife, like the classic KA-BAR, whose blade is only 7-in long and which has a small serrated edge that satisfies the rules.
https://mk-law.co.uk/new-law-targets-zombie-knives-and-mache...
Oddly specific rules though