By Vicky Shaw, PA Personal Finance Correspondent & Lawrence Matheson Motorists opting for monthly insurance payments could be hit with interest rates as steep as those on credit cards, with some facing nearly 40% APR, consumer watchdog Which? has warned. The investigation by Which? also revealed that home insurance customers aren’t faring much better, with some providers charging close to 35% APR for those spreading their payments across the year. Which? highlighted that the interest rates slapped on monthly insurance premiums are starting to mirror those associated with credit card debts. In …