I do not want to decry your memory Geoff - but I would ask if others share it, or if they share this memory of mine of the same period you quote.
Private landlords were very few, providing two niche markets of executives with temporary contracts and students in shared accomodation.
The majority of working people obtained housing either by buying it, or a significant minority rented their home for the local council. There was also a small but successful RSL sector meeting specific and special needs.
People waited weeks (yes weeks) for housing because of the plentiful supply. Tenants wanting an exchange simply posted a card in a shop window near where they wanted to move to, and invariably found a match almost immediately. Access, availability and flexibility were no problems, and housing was well maintained, normally by an in-house council worker who had all the tools he needed in a box on the front of his bycycle.
Rent were highly affordable, about a 10th of current social rents in real terms, and this enabled tenants a decent standard of living, including annual holidays, on a single household wage.
The shabby conditions may have been in the private sector, and may have been because of rent controls. Perhaps arguing to ease such controls may have been better than the solution that was bought into play.
Councils were banned from building and RTB ensured half the stock disappeared. Rent subsidy was successively reduced to such a degree that landlords could no longer afford to capitally repair the homes (hence the decent homes funding being required), and to such a degree that lately rents have raised more than the landlords recieved to manage thier homes.
It is the past 30-years of policy that has given rise to the housing situation that matches your memories of 40-years ago.
I'm sure that there were areas in Britain where waits for housing were longer, repairs not as good, and being able to trade down or trade up the size of your home was not as simple - but the memory I quote was real and experienced in the Essex community where I was a tenant at the time.
The statistics of housing by tenure for the 1970's also show virtually no private landlords compared to a massive social sector, which would tend against the memory you are calling upon Geoff - are you sure that you do not mean the 90's?