I'm not going to get into the upgrade issue, I wasn't pushing for anything, I didn't want an SUV or an automatic (I greatly prefer manual's when i'm home in the UK) - I would have gladly taken whatever was offered providing it was clean and within the category I had booked. The car I was assigned was neither.
Of course a puncture could have happened in any car and I dealt with it in the same way I would with any car. I put the space saver wheel on until I could get it to a repair shop. I don't have an issue with that or really the mechanical fault. This happens. Especially on brand new cars that have been sitting on the lot for a long time as the Kia had.
The point is, Hertz offered no assistance. The breakdown number they provide, goes to the AA. The AA re-directed me to Kia Support. Kia Support re-directed me to the RAC. The RAC redirected me to a local breakdown service who was able to re-set the error codes but advised me to take it to a local Kia garage or better yet, back to Hertz to swap it out. Had I been much closer to a Hertz location, I would have gladly done so.
Hertz Breakdown couldn't offer any other solutions as they said they were only authorized to offer breakdown assistance. Obviously. They said I had to speak to Hertz LHR to advise. Many hours of calls with Hertz Customer Service - the lovely folk in the Dublin office resulted in nothing. LHR just never answered the phone and the CS Agent told me that LHR is notoriously terrible at picking up the phone. It's just the lack of support that I find really disturbing and contrasts enormously with my experience of Hertz in the US.