So looking at GSV, the suspension affected the first three properties from the start of the parking bay. 240 is outside the bay by the built-out kerb. Your car is clearly parked in the suspended area, at No 236, if I'm right. The suspension sign is only a few yards from your car, yet you say you never saw the suspension notice. Yet your wife saw the PCN envelope, yet not, it seems, the suspension sign itself. Frankly, in my opinion, you are going to struggle to overturn this PCN, as you were resident in a nearby property when the sign was put up. I'm quite puzzled why either you or your wife never saw the suspension sign, or maybe you did, but ignored it.