I've made the pictures of current state of signs which are uploaded here https://drive.google.com/drive/folders/1ycI5fCQJOmERKp0xB715p4yIVLiK2YNA?usp=sharing
It looks like these specific signs shown on the camera are closed now which is weird, but there are at least two signs on adjacent street which leads to this path.
It is also worth noting that if you see these signs and decide not to proceed, what do you do then? You can't turn around on the spot
The signs at the turn are closed/not displayed because this is a 'school street' restriction - a timed restrictions on motor vehicles passing by a school at pick up and drop off time. It is half term and the restrictions only apply during term time.
You've also captured the advance warning sign which give you a heads up that there is a restriction in advance of the left turn.
If the restriction applies to you, and you missed the advanced warning sign, you would treat it in a similar manner to a 'no entry' sign (i.e. stop, check mirrors, signal, and merge into the lane heading straight across the junction rather than left)