It had to be the Shepton! Have just come back from a holiday there and although couldn't visit any of the caves on Sao Miguel it all looks very interesting indeed. There are over 200 recorded caves on the islands some of which contain stal due to secondary deposition. The wife would go diving however but not caving. They are a lot easier to get to than appears, have a nice mild climate, plenty of camp sites and the cost of living is low so would make a nice caving holiday destination for vulcanospeleolgists! The caving organisation out there has it's own web site - all in Portugese unfortunately.