I'm on my 5th SLK. Had a slk230K, slk350, a mental 352bhp slk32, back to a slk230 and currently a slk250 cdi. I think they are great cars, really under rated but suits my style of driving perfectly, ie lazy one hand one foot cruising and I've been all over Europe in one.
The diesel does have the diesel rattle but it does not bother me in the slightest. I get 600 miles to a tank, 200bhp and the figure of 500nm of torque beats a E92 M3 V8! At nearly three years of ownership the car I have currently is the longest I've ever kept a car so that says something.
I've also fitted a IWC clock to mine to combine both of my interests :)
I'm near Glasgow if you would like a drive of mine to see if you like before you buy with no pressure of the sale hanging over you.
Here's my one.
Just noticed you in Fife, I'm 20 minutes from the Kincardine Bridge, so you're probably not too far away.