Mister_e,
Slowing the baud rate didn't do it, I tried in my mind to justify why this error occured with a 4 line LCD but not a 2 line VFD,so I tried a different LCD and still got the same errors. I started with the hypothesis, maybe the LCD was using more power than the VFD, causing the pic to brown out, I tried a 1000uF capacitor on the pic VDD (power in) pin and that didn't help. I moved it to the LCD terminal 3 (the contrast line) and viola it stopped making the errors, however it required the LCD to be initialised and then a PIC reset to work. I replaced the 1000uF cap with a .1uF bypass capacitor and all is as it should be.
Fat Dumb and Happy again!
JS