Personally, I can't stand Siesta - maybe something to do with my parents having a set way after they stopped being fashionable! And £30-35 is way out of line with what they sell for on e-bay (if they sell at all).
But you all know about my passion for the screen-printed tumblers (even if they're not worth much - yet?
), and other ranges such as Five Star (1968) and Vista (c1970) won Design Council awards in their time...
I think the £35 set may have been a later addition to the range, Nic. According to Lesley Jackson's C20th Factory Glass, Siesta was designed by Alexander Hardie Williamson in 1973 (the year before he retired) and added to by John Clappison in the later 1970s.