Morris Minor Owners Club

Good though a 5-link set-up is, I think it's a bit of an overkill unless you're running 150+bhp. If you're looking at upgrades for a daily driver, to make it more user friendly, I'd suggest uprating the brakes (to prepare yourself for MPVs/School Run 4x4s driven by people who see texting as their no.1 priority), improved rear axle location (anti tramp bars/radius arms), and removing 2 leaves from the rear springs to soften things up (better weight transfer for traction, and reduced oversteer), possibly uprating the dampers (telescopic conversion, or thicker oil in the lever arms). All this can be done at minmal cost, if it's not enough then look at other options.
By the way, I've yet to find another car with steering as good as a Minor!