I have heard of the grand total of two of these in various peoples hands. Never seen one myself and I reckon its extremely rare as its one of the early Relums. Would certainly buy one if I found one for sale.
Value would depend on being a Relum/FEG nut, like me, as a big Tornado goes for around £60 in good condition, the rarity of the baby mght make it slightly more valuable. However its an anorak/collectors only item I would have thought...