What to do if you ignored the ticket?

Having been ticketed, he Googled and found advice just to ignore the ticket, which he did.

I’m sure he jumped at the opportunity to bury his head in the sand, after not checking the date of that advice! Great innit, the bogeyman disappears as soon as the eyes are closed!

Now I've told him that, to my understanding, things have changed and this isn't the advice any longer.

Correct. Ever since October 2012.

http://www.legislation.gov.uk/ukpga/2012/9/schedule/4/enacted

We've read through the newbies thread but of course the time for appeal is up.

Not very thoroughly it would seem.

No Notice to Keeper has been received.

It won’t have been received if it was a windscreen ticket. That will come between days 29 and 56 after the parking event.

What's his best course of action now?

If the parking event was 3/11/17 then he’s just missed the opportunity to head off the NtK around day 26, so he now has to wait for the NtK and them deal with that as per the sticky. He needs to read the NEWBIES FAQ sticky, post #1.

The parking charge issuer is UKPC, a BPA member.

Fortunately POPLA is open to him and UKPC can be beaten there. But he needs to get his head out of the sand, read and thoroughly digest the sticky, especially post #3 once the PPC rejects his initial appeal.

I've read post 1 of the sticky but I'm a bit unsure,

Why are you reading this? What’s your friend doing to get himself out of his own mess. There’s a real danger of Chinese Whispers here, which can end disastrously. Get him off his backside and on here reading this. His time with his head under the pillow has passed.

....... the instructions for the BPA companies seem to apply for sending your appeal around day 26, which has now been exceeded.

Then it’s await the NtK.

Should you obtain the registered keeper's data from the DVLA without reasonable cause,'

Change to ‘Should you have obtained .......’, but only after receipt of the NtK.

Once the NTK comes, he can still then ask UKPC for a POPLA code?

He doesn’t ask for a POPLA Code. He sends in the initial appeal. If UKPC reject the appeal, they are obliged to issue a POPLA Code. But expect there to be an interim letter from them after the initial appeal, asking for the name and address of the driver. This is to be ignored, then after 35 days there will be a formal rejection and POPLA Code.

This is unlikely to be sorted much before March next year.

Another thing I don't really get is on what grounds he could reasonably appeal. He doesn't dispute the signage is there or that it's clear, he's just one of those people that walks round in his own little world and didn't notice it. He didn't use the Matalan store, he used a store a couple of doors down which doesn't have its own car park, so he can't provide proof of a purchase. I appealed a private ticket about 5 years ago by asking them to demonstrate how my parking there for a short time had caused them a loss amounting to £xxx. Is that now a no go?

He needs to be doing plenty of reading himself. You cannot possibly do all this for him, as clearly you are making incorrect assumptions about signage - as a starter. There are thousands of threads of a very similar nature all appealed successfully using the NEWBIES FAQ sticky, post #3 (which will come after receipt of the POPLA Code).

You are correct on one point - ‘no loss’ is dead in the water.

You/he need to go back and thoroughly read the NEWBIES again, and again, until you/he start to understand the process.

Parking scammers lie. UKPC are one of the worst and got caught doctoring time stamps on their photo' "evidence."

I will be very surprised if the UKPC signage is adequate and meets all the BPA requirements in every way. I doubt their NTK will meet the very strict requirements of the POFA 2012 either.
So, you/he needs to read, and then go through the two stage appeal process.
The initial appeal is already written out to just copy and paste, and there are loads of appeal points available in template form in the NEWBIES.

Get stuck in and stop thinking like a victim.