As I recently turned 70 I have had to renew my driving licence, getting my first photo licence in the process. I knew of the DVLA losing motorcycle entitlements so before I applied for the new licence I rang the DVLA.
The woman I spoke to confirmed that they had a motorcycle entitlement on my records, but did admit in the course of the conversation that there had been problems with losing such entitlements. I was given the impression that the problem had been sorted, but nevertheless I took the precaution of photocopying my licence before sending it to the DVLA.
My new licence arrived with my motorcycle rating intact which isn't bad considering that I passed my test in January, 1956! Back in the 80's a colleague of mine at work did lose his motorcycle licence when he moved house and had to retake his test. After over 20 years it is an absolute disgrace that this problem is still happening, as evidenced by your article and postings on this site.
Can you imagine the outcry if all the caravanners lost their trailer entitlement whenever they changed their licences? Yet our problem seems to be met with a deafening silence from the media in general, only surfacing in the motorcycle press.
I can only suggest that all motorcyclists phone the DVLA as I did before sending in their licence, not forgetting to take the name of the person they speak to, and photocopy the licence before sending it. It just might get it through to the DVLA that they have a problem and it should have been sorted twenty years ago!