Tyre Trouble - a cautionary tale

This may not be exactly on topic as it was the car I had a problem with recently.  Early in the year I had new tyres on my car - and shortly afterwards picked up a bolt which punctured one of them.  Local fitters mended the puncture and sent me on my way.  Last week en route to collecting my new caravan the car showed a Tyre Pressure warning light - I dropped into a local garage and they topped up the pressure and told me I was fine to go on.  The light eventually went out and I collected the caravan.  A couple of days later the warning light is on again - so as I was headed for Lincoln I dropped by a Kwikfit place - where they found a nail in the tyre - fine we can fix it for £25.  Once they had the tyre off they called me over and asked who had previously repaired the tyre.  The fitter told me it was an illegal repair and in the event of an accident the loss adjuster would be very likely to spot the repair and declare my insurance null and void!  He said he was unable to repair the second puncture because if he did he would get the sack! He advised me to go to Trading Standards.  I felt I had no choice but to wait until a new tyre could be delivered.  While waiting for a time on this I chatted to a fellow customer about how awful it was that people could send me off with an illegal tyre - etc etc.  When I returned to have the new one fitted the chap taking my money said he had heard me talking - but had to point out that it wasn't illegal as such - just a touch ill advised.  Hmmm - set me wondering who had been doing the wrong thing!  I claimed the old tyre as "evidence" and a male friend took it back to the original tyre place who fixed the puncture for nothing and informed us that Kwikfit are on commission for every tyre they sell!  I knew I didn't go to them for a reason - but fixing a puncture seemed a reasonable idea!  I am now sending the story to Trading Standards!