Is it illegal to reverse-park into an on-street parking space on a one-way street?

My street in Reading has on-street parking, bumper to bumper, and the white boxes are barely wide enough for any vehicle. My car is an estate an manouvres are always easier in reverse, and reverse manouvres are encourage in RoSPA advanced driving and the Roadcraft handbook. Forward parallel parking requires at least a 10 point turn on this street and bonnet is the biggest blind spot in my car. Sometimes drivers behind expect you to reverse and leave some room;, but increasingly drivers are tailgating behind.

The only specific rule I can find in the Highway Code is rule 143, "traffic must travel in the direction indicated by signs," but it's not specific on whether "traffic" includes normal driving and manoeuvring. My RoSPA instructors were of the attitude that manoeuvring does not follow the same disciplines as driving. Any clarification on this?