I did exactly this. I do 90 miles a day, so sold my zed and went for a BMW 123d coupe. 0-60 in 6 seconds, RWD and 50mpg. I actually find mine handles better than my 313 zed did. Sure, not as much fun and a whisker slower on the 0-60 but its a cracking car. Its nice, relaxing, luxurious, comfortable drive for my daily commute, but when I want some fun, it give me a big smile. It also is surprisingly quick.
I did consider this and actually used my wifes old 307HDI for a while, but the insurance was the killer. Even multi-car policys only let me use the NCB on one car at a time, so even though i had 20 years NCB on the zed, They gave me none on the 2nd car, resulting in a huge insurance premium. Then when I factored in the monthly running costs - tax, servicing, mot etc... it all just added up. So, selling both the shed & zed and running one car worked out the cheapest option. Certainly something the OP can consider tho!