Geoff, I would suggest you soak the motor in WD40 or something for a bit. Remove the head, backplate and then remove the sleeve. If the piston liner (sleeve) will not come out you may need to carefully apply heat to the assembly with a bernzomatic, stove etc and then force the sleeve from the bottom with a popsicle stick and then pull it out. Then lightly mark the back of the rod so you can put it back in correctly. Rotate the crankshaft carefully to bottom dead center. Use forceps or needle nose  pliers to romove the rod from the crankpin and you should be done. It usually takes some time and frustration but if you are careful it should be no proble.
Wayne

Hi Goeff, I have found that many FP's and others have too tight a fit of the wrist pin in the piston and as a result tend to weld themselves together! Use a strong solvent for a day or two and then if the connecting rod won't still move back and forth easily, put an allen wrench of about 1/8 thickness or so in a vice grip and pull the connecting rod loose from the piston/ wrist pin weld! Use a rag to hold the engine so that you may get a stronger grip on the engine. Once apart use some Flitz or rouge to loosen up the piston/rod tolerance. In addition drill a small hole in the top of the connecting rod to serve as an oil access hole. Champer the hole with a small counter sink to serve as a well to catch the oil and help to admit it to the wrist pin. Note that the bottom end of the connecting rod already has a hole run through it to serve in the same fashion! Hope that this helps!

But Phil, I still gots my own teeth.