Hmmm, actually some geezer approached me at a trade fair to ask about my FL. He wanted to know if the spare was the same size as the rest, apparently when he bought his the spare was only 15" and the LR Dealer said it was to save money and that loads of FLs come with smaller spare!!! Told him mine was a proper bigun and he left me alone!
Could be some truth in what your heard or read. Lev