Free Traffic Legal Advice

So why didn't you use Beresford Road to get onto Green Lanes ? Are you new to living in Allison Road ?

London is absolutely riddled with restrictions like this, and one must be very alert when driving on narrow residential streets. Looking around using GSV, I see you cannot use Hewitt Road because it's Left Turn Only at the top, probably because of the queues at the traffic lights, so it's either Beresford Road, or Duckett Road. One can use Pemberton Road outside the restriction times, of course. The restriction times indicate it's for a school or nursery, and a brief virtual tootle along Pemberton shows there is indeed a school there: -
 https://maps.app.goo.gl/MgNhFm5sxYw4Du1T7

Frobisher Road is similar, due to the presence of the Busy Bunnies Nursery on the corner: -
https://maps.app.goo.gl/kmSZEQy4LbMwUXpE8

As you say, there is a warning sign, so its difficult to think of a robust appeal: -
https://maps.app.goo.gl/MgNhFm5sxYw4Du1T7

You could go for the height of the restriction signs. If you can show how they appear from a driver's view point it would help an appeal as collateral.

I assume you are not an SS41 permit holder, as they are permitted at all times.

Thank you for your quick response
I don'tnow what ss41 means
Using Beresford Road means a right turning into a yellow box - more risk / complicated

I was in a column of traffic on Wightman Road, no time to see sign
I've lived here a long time but don't drive much - certainly not down that road

Permits are coded. Do you have one ? The sign allows permit holders with Code SS41 to pass the sign.

The Gazette entry gives this:

(f) School Street Zone SS41 - South Harringay Junior School: Timed pedestrian
and cycle zones in which motor vehicles, except for those issued a permit would
be prohibited from entering, Mon-Fri 8:15-9.15am 3.00-3.45pm during school
term times and when the appropriate signs are on display on the following road:
Pemberton Road N4: From its junction with Wightman Road to its junction with
Green Lanes.
Those eligible for permits include properties and residents of Pemberton Road
N4 (all properties), 487-489 Green Lanes N4 (odd), South Harringay Junior
School, Mattison Road N4, The Ladder Play Centre, Mattison Road N4, 118-120
Wightman Road N4 (even), Medical practitioners attending those residing in the
zone, disabled badge holders who reside outside the zone but require essential
access and school buses and vehicles used in the transport of children and
adults with special access needs in relation to South Harringay Junior School
within the zone. All vehicles will be allowed to exit the zone whilst it is in
operation.

https://www.minutes.haringey.gov.uk/documents/s144022/Appendix%20D%20-%20Proposed%20traffic%20order%20notices.pdf

Term time?