All the ppc has to do is show, on balance of probability, that the first pcn was correctly addressed, postage paid & put into the postal system.
They do not have to prove that it was delivered.
In fact, once they've done the above, the burden of proof falls to you to prove that it was NOT delivered. 
https://www.legislation.gov.uk/ukpga/1978/30/section/7
Absolutely WRONG!!!!! If challenged, the operator must prove that the notice was actually entered into the postal system. It is not enough to simply assert that it was.
Under the
Interpretation Act 1978, a notice sent by
first class post is
deemed to be delivered (i.e., "given") on the second working day after posting — but
only if it was properly addressed, postage paid, and posted by
first class.
You only need a free Proof of Posting certificate from any post office for this presumption to apply.
Private parking companies do
not generally post items themselves. They outsource to
mail consolidators using hybrid mail services. These consolidators print and dispatch the mail, often using bulk business postage that does
not qualify as first class.
What the operator typically tries to rely on is the
handover receipt from the mail consolidator, claiming this proves the date the notice entered the postal system. It doesn’t. At best, it proves the date the item entered the consolidator’s internal system —
not the Royal Mail postal system.
I will confidently wager £100 that any "evidence" they provide from the mail consolidator will not show the use of Royal Mail first class post. Instead, it will show a
2–3 working day delivery service, which is not deemed delivery within two working days.
Only
first class post qualifies for the two working day presumption under both the
Interpretation Act and the
Civil Procedure Rules. If they’re using a slower service, then
three working days minimum should be allowed for delivery — and that must be reflected in any procedural deadlines tied to the date of service.
