Mmm, I just read that with extreme interest, as the same kind of thing happened to me recently. Only with a different set of licences.
I lived in the Midlands mostly, between working away and travelling, until 2003. Then emigrated to New Zealand. I took with me my UK licence which had a HGV1 learner component but not higher, as I failed the test and didn’t continue with it. On arrival in NZ I converted my licence over to a full car and they generously gave me learner classes for everything else up to the max, a Kiwi Class 5 HT. As I had more time and money by then, I did a course and passed everything I could so then held a full licence for car, truck, trailer, agricultural, rollers and bulldozers (Wheels Tracks and Rollers endorsement) 
Come to 2006, I was back in the UK for a holiday and went to hire a van to move the last of my stuff. The desk girl looked at my old paper UK licence and told me it was no longer valid as it was not a photo ID jobby. Big argument ensued as it has printed on it ‘expires 2035’. I went out, and just in case she was right I called DVLA. They said if it was a straightforward car licence, yes, it would last until 2035, but the provisional HGV bit made it expire earlier as I needed a compulsory medical at 45 and without that it would cancel the entire licence. I said I wasn’t quite 45 yet, few years to go so all good eh? Still no good, they then said it was an offence to drive without the correct new photo licence. Anyway my brother in law hired the van for me so I never got to the bottom of it all. 
By 2011 I had become a full NZ citizen so I could then work in Australia as an automatic resident. They were in the middle of a mining boom so I got on a plane.
The Kiwi licence was still valid (until 2014) so with this in hand I got hold of an Aussie car, truck and trailer jobby. Easy as anything and they don’t cancel the parent licence.
All good until this year, when I went over to NZ for a well deserved holiday. I dragged my car out of the barn it was languishing in, serviced it, cleaned it and took it in for a Warrant of Fitness and then pay the Registration cost. The staff there said hey your licence expired last year! I had completely forgotten about it. They said quick go over to the driver licencing office in town and renew it. These said to me I would need a medical to renew all the vocational classes, and gave me a form to see a doctor. But I tried and couldn’t get in at short notice, more like 2 or 3 days wait. So I asked how long will it be before all my classes expire completely? They said 5 years. I said, no worries I will just drive on my Aussie licence for the remaining couple of weeks. Staff said no, as a Kiwi licence over rules an Aussie one or any other nationality, and if you get pulled up you will be fined for having no licence! In spite of having 2 current overseas ones! They wouldn’t budge, and said look, just cancel your Kiwi licence and all is good! Get lost. 
Anyway I went back to the inspection centre and they saw the funny side and agreed to process the paperwork on the old UK licence as then they could claim they thought I was a recent immigrant and didn’t know better. I then hid both my down-under licences and kept the old, falling to bits UK paper licence handy in the glove-box for the rest of the trip. 