OP, IMO this case has implications beyond your case, hence the length of my suggested draft. Clearly I don't know the sequence of your events and would apply to any user in principle but whether to you in practice I don't know.
I parked;
I saw the traffic sign immediately ahead which showed that the bay was pay and display and indicated where the machine was located;
There was no other information on the sign indicating that the bay was anything other than operational;
On returning to my car to display my BB, I saw what I now know from the CEO's photos to be a hood but thought this just indicated that it was out of order and as I was exempt from paying did not need to examine further;
I displayed my BB as required and left.
On viewing the CEO's photos, these confirm that other than for the hood, nothing was displayed to indicate the suspension, contrary to regulations, neither did the cover itself indicate the period of suspension, again contrary to regulations. On this point, a suspension is effected pursuant to an enabling power within an order. It has terms and a time period. It does not exist simply because a hood is placed over a machine. I invite the authority to consider the point that it must be axiomatic that there was no warning of this suspension because it only purportedly came into effect when the hood was placed which, according to the authority, immediately brought the suspension into effect.
If this is the authority's standard practice then in addition to being unlawful* in parking terms, it is also discriminatory because any motorist who consults the same sign as me who is of a payment-exempt class has no need or obligation to approach the machine and examine the hood. I strongly suggest that the council's practices needs to be reviewed. If the authority wish to suspend such a bay then all traffic signs pertaining to the bay must carry the signage otherwise, as in my case, a BB holder(or any other payment-exempt class of user for that matter) would be misled.
(*- by unlawful, I refer to the authority then imposing a penalty when prescribed procedures have not been followed)
The PCN must be cancelled.