Clive,
I feel your pain. My situation was not quite the same, but I think there are similarities. I sold my 964 when my daughter was born because we could not fit a car seat + baby pram + diaper bag into the car. We also had a family car with more than enough space, but I thought I needed to be more practical etc and sold the car.
For about a month I was able to convince myself that I did not miss having a Porsche in the garage...after all I was very busy with our new born daughter. But as the months went on I got grumpier and grumpier because I did not have a hobby car. After about 10 months my wife could no longer take my moaning and sobbing and told me to go buy a Porsche if it will makes me happy. Needles to say I was on the web hunting within seconds!
I still went the more practical route and bought a Porsche that can handle a baby buggy, diaper bag and more i.e. my 968 Coupe, but the moral of the story is.
If you have a true passion for a marquee you should never be without one, even if it is a cheap fixer upper. However, if you see Porsche as just another premium car brand like BMW or Mercedes, by all means go for the Merc.