What you are really trying to achieve is cancellation of the PCN so you pay nothing, because that avoids the £160 charge, the loss of the discount, and the later enforcement route if it is ignored. Ealing says you must challenge the PCN first, and if they reject it the next stage is an appeal to London Tribunals; if you go that far you are dealing with the full charge, not the discount.
On what you have shown me, this is not really a red light case. The notice says 32JD, meaning the council allege you failed to follow a blue mandatory direction sign and went the wrong way. If the CCTV shows a clear right-turn-only sign and your car going straight, the core defence is weak. "I did not realise" and "I thought going straight was safer" explain the mistake but usually do not defeat the PCN. The real issue for an adjudicator, meaning an independent tribunal judge, is whether, on the balance of probabilities, meaning what is more likely than not, the council can prove the signed direction was clear and that your vehicle did not follow it.
Your best point is evidence, not sympathy. Ask immediately for the full CCTV and check the junction yourself. Was the blue arrow plainly visible, unobscured and positioned so a driver in that lane would actually see it? Were the road markings worn, confusing or inconsistent? Does the video clearly show your vehicle disobeying the sign, or only part of the manoeuvre? I am assuming you are also the owner, meaning the person legally pursued for payment; if you were not the owner, or the vehicle was sold, hired, taken without consent or the PCN was served late, the position changes materially.
My candid view is arguable only if the signage or video is genuinely poor; otherwise prospects are weak. The council's best answer will be simple: clear sign, clear CCTV, driver error. To reduce that risk, make a representation, meaning a formal written challenge, within 28 days, focus on signage, visibility, lane markings, camera angle and any defect in the PCN, and do not waste space on not knowing a PCN could be issued. How far are you willing to push this if the discount is lost, what dated independent material do you have, and would you accept paying the discounted amount if the video is plainly against you? The next milestone is to obtain the video and page 2, then decide quickly whether there is a real evidence point or whether this is one to pay at the discount.
