On street parking rules

Opposite our flat we have two yellow lines at right angles to each other with the words 'KEEP CLEAR inside the line facing us.  To the left of that, there are double yellows on the road by the pavement.  There is no access to park on the land behind without crossing the single yellows.  A resident opposite has a garage the other side of the yellow lines.

I'm clear that parking alongside double yellows could lead to a fine.  But I always understood single yellows to mean no parking at certain times, with a notice nearby specifying those times.  There is no such notice here.

In England, a vehicle blocking a resident from exiting his garage to join the highway would lead to the offending vehicle being towed away (but not for preventing said resident entering the garage).  But I don't believe that these single yellow lines and script with no regulatory notice specifying the times that parking was not allowed, are enforceable.

Can anyone help please?