Well, that seems to be very reasonable, especially since the two most expensive sweeties in the region (in that Sherryish profile) are retailing for about 35-55. The quality of the wine is a mere suppposition on my part, though, but reputation is good. Surely it sold for less when they were in business, but since then many other wineries have adjusted prices to something that more accurately reflects what's inside the bottle: so very often it's absolutely top stuff, held in a solera for 20-40 years WITHOUT seeing any profit other than the sales of a limited number of bottles...it used to be ludicrously cheap. I can inquire (second-hand info) or scan that Decanter letter for you.
BUT if you want a couple of tips for similar stuff that I HAVE tried and is priced in that range, even below over here at least, I will gladly offer a few names too.