There's another thread running on this new bus gate. A tyical move to make money dressed up by council b**lsh*t as an improvement : -
https://letstalk.enfield.gov.uk/nmh-ati?tool=qanda#:~:text=The%20proposals%20feature%20a%20two,modal%20filter%20at%20Amersham%20Avenue

Your GSV link doesn't seem to take you anywhere near Bull Lane. GSV is not up-to-date, so doesn't show the bus gate, nor any advance warning signs.  If you want to fight this one, we really need to see what advance warning is given. Of course you could submit representations on the lines of being a patient at the hospital.

Just read the absolute bu+lsh*t here : -
https://letstalk.enfield.gov.uk/nmh-ati/news_feed/bull-lane-bus-gate#:~:text=The%20bus%20gate%20at%20the,gate%20location%20will%20be%20removed.

First off, to get to the adjudicators, (Traffic Penalty Tribunal), you first have to submit reps to the council.Only when they reject your reps can you take them to the TPT. When rejecting, they will no doubt say everything is OK, and possible re-offer the discount. If they do, you have to weigh up the matter. If they don't, it is a total no-brainer to take them to the TPT, as the penalty doesn't increase and there are no additional costs.
Assuming the advance sign is what I posted, I think you have a reasonably good case, but we can never predict what an adjudicator will decide. Certainly if you take the TPT path it is essential you ask for a telepone hearing with an adjudicator or even a hearing at their office. You must convince an adjudicator that the advance sign is totally inadequate. I think it is, but it's not me you have to convince.

The video shows you totally bang-to-rights, I can't see anything that might contradict this opinion. Two clear 'No Left Turn' signs with nothing in the way of them to prevent you seeing them.

Of course there may be a fatal error of content in the PCN or the traffic order may be out-of-date. If there is something, you'd inevitably have to take them to London Tribunals for an unbiased decision. This means the discount option wouuld be lost.

GSV view is not up-to-date, so you'd need to take photos that could show bad signing. Their sole evidence is a video, so you and us need to see it.  It may be possible to download it from their website.

They say the signage is adequate, so the only way to resolve this is to take them to TPT. This means risking the full PCN penalty.
If GSV is up-to-date, please post a link.

Having now seen the video, I am more certain than I was that you will struggle to overturn this PCN. The advance sign is a correctly formatted advance warning sign of a restriction at the next turning on the  left.

Your links don't work, probably because you have cut-and-pasted them. You need to re-post them afresh here.

It looks like you have fallen foul of this new scheme: -
https://letstalk.enfield.gov.uk/nmh-ati?tool=qanda#:~:text=The%20proposals%20feature%20a%20two,modal%20filter%20at%20Amersham%20Avenue

They have acted reasonably and not forced you to adjudication.
Well done !