It all depends on whether you are prepared to take them to the Traffic Penalty Tribunal. This means risking the full PCN penalty. There was a case there in 2018 decided by Caroline SHeppard, the Chief Adjudicator at the time, now retired that ruled that requesting the CAZ fee as well as the penalty on the PCN was unlawful.
Case Number : IA01249-1803 Decision Date : 13/06/2018
Extract from the decision
Regulations 7(3)(g) and (f) require the penalty charge notice to state:
(f) the amount of penalty charge that is payable if the penalty charge is paid in full—
(i) within 14 days of the day on which the penalty charge notice is served;
(ii) after the expiry of such 14 day period but within 28 days of the day on which the penalty charge notice is
served;
(iii) after the service of a charge certificate;
(g) the manner in which the penalty charge must be paid and the address to which payment of the penalty charge
must be sent.
The clear intention is to set out clearly the amount of the penalty charge to be paid, and give
equally clear instructions as to how to pay the relevant amount.
While the PCN in this case dealt with the amounts of the penalty charge, according to when
they would be paid, it also stipulated that:
“In addition to the penalty charge you must also pay the applicable road user charge of £3.”
And the PCN further required Mr Moran to pay £38 or £73 (the relevant penalty charge with
£3 added), without an option to pay just the penalty charge.
There is no power in Regulation 7 for the PCN to require the road user charge to be paid in
addition to the penalty charge. Nor is there a power for the charging authority to refuse to
allocate a payment made for a crossing to that crossing, and hold it, possibly indefinitely, for
future use.
It is not in dispute that Mr Moran had paid the £3 crossing charge, as evidenced by his receipt
dated 14 January 2018 for the £3 payment, and accepted by Dart Charge.
It is all very well to set out the amounts of the penalty charge, but the impact and effect of the
PCN is to demand an amount that is in excess of the penalty charge, and it implies that
payment of £38 or £73 is the only amount that will be accepted.
(my bold and underline)
So far, Bristol have never let this get to the adjudicators for obvious reasons, so you could submit representations that their request for £69 is unlawful as it exceeds the PCN penalty.