So you did not receive the PCN before the 28 day period had already expired, in these circumstances I'd suggest you're entitled to make a witness statement on the ground that you did not receive the penalty charge notice.
However in order to do this, you need to wait for the debt to go back up to £198, then file a witness statement (not a statutory declaration) using
form TE9 (you can fill it in on your computer, no need to print as the court will accept a typed signature) and email it to tec@justice.gov.uk with the PCN number in the subject line.
Remember the applicant is Bristol City Council, not you (you're the respondent).
The reason we warn against contacting the council in these cases is because, as has happened in this case, doing so simply delays the whole thing, sometimes by several months.