Free Traffic Legal Advice

This used to be a Mon-Fri restriction and less hours too, but was changed fairly recently to the present restriction. 
OP, did you ever look at the sign when parking all those years ?

You posted in Pepipoo and MMV Redux found the update, which is part of a raft of changes
https://www.thegazette.co.uk/notice/4400304
I then trawled through it and found the changed restriction: -

Quote

(v) in Old Town, the north-east side, (i) extend the operational times of the existing loading bay opposite The Polygon so that it operates on Monday to Sunday between 7am and 7pm; and (ii) relocate the existing loading bay opposite Nos. 32 to 36a Old Town to opposite Nos. 28 to 32 Old Town; and (iii) introduce double yellow line “at any time” waiting restrictions opposite Nos. 32 to 36a Old Town;

So if you're up for it, Mr Mustard will diligently represent you at London Tribunals.

Thanks Incandescent. Ah yeah I do remember looking at the sign the first time I parked but it never occurred to me that parking restrictions might change so never looked at it again after!

Yes, you're right these are recent changes and I've gratefully accepted Mr Mustard's help 

That's very kind, thanks for your offer, I'd be grateful for your representation.

Have emailed you using my hotmail email address.

Hello

I have been parking in this exact spot on most Saturdays for the best part of 4 yeras (except for during covid lockdown). I have never received a PCN or parking fine and I don't think that spot used to be a restricted loading space, but I don't know for sure. There are lots of free parking spaces that look exactly the same along the same street. I'm pretty sure I'd checked parkopedia and signage when I first started parking there, but have no idea at what point that space turned into a restricted loading space.

I parked at 9am as normal the Saturday just gone (9th Sept) and on my return was surprised to find a PCN. If I'd known it was a restricted loading bay, I would have parked in one of the other free spaces on that street, or in a nearby street.

pcn front - https://imageupload.io/kU6qMQkaytDs6gz
pcn back - https://imageupload.io/4PSLFTR87KCrXTG
pcn sleeve front https://imageupload.io/4aRL5ifWx4uWsZs
pcn sleeve back https://imageupload.io/fRtmA4jlGdSst5S

Location streetview - https://www.google.com/maps/@51.463309,-0.1...i8192?entry=ttu

To view PCN on Lambeth Council website - https://pcnevidence.lambeth.gov.uk/pcnonline/index.php

What, if any, grounds do I have for appeal?

Any help appreciated.