Highway code says "You MUST NOT wait or park on yellow lines during the times of operation shown on nearby time plates (or zone entry signs if in a Controlled Parking Zone) – download ‘Traffic signs’ and ‘Road markings’. Double yellow lines indicate a prohibition of waiting at any time even if there are no upright signs."

I would take that to mean you can park unless there is a sign with times when it is prohibited.

The signs and lines represent a traffic regulation order made by the local authority. You get a ticket not because of the lines, but because of the TRO. Typically the TRO is made before the signing and lining takes place, so it should already be in force. However, if the signage is not complete then it will be an easy appeal against any PCN deopendant on that signage.

At least your car wasn’t parked there, and a crane truck lifted it up, they painted the lines, put the car back down, (facing the other way), then put a ticket on the car! It apparently happened to a bloke in London, and the council denied it happened and upheld the ticket. Until he was able to find CCTV footage from a business on the other side of the road!

As above, AIUI. A single yellow means "what it says on the sign."

Be very wary of the sudden appearance of very small signs.