But you should be happy Simon
The Grayling record in the Algarve is a monster record, IMO. I don't know of other records there, but it's possible other people have such info (e.g. Nelson Fonseca, Eduardo Marabuto). According to the info I have, Lagoa de Santo André is the southern limit (as an isolated record) for the species, and Grayling is only regular and common north of the Tagus (north of Santarém). So it's really much better than a Tree Grayling record!
Where exactly did you see that one, did you keep a note? Were there more?
Rock Grayling (Hipparchia hermione or alcyone, depending on the author) and Grayling (Hipparchia semele) are really different species, perhaps Grayling should be called Common Grayling to avoid confusions. Grayling is a smaller species (Rock is quite large actually), and although the underwing (hindwing) pattern is a bit similar between both, you'll notice the shallower shape of the dark discal band on Rock, and a longer wedge shape on (Common) Grayling; the underside of the front wings is very different though, being usually of a bright and beautiful orange tone (buffish to orangish) on the
basal area on Grayling, and very dark brown on Rock, but the front wings are often hidden, or not fully exposed. Rock is only present north of the Tagus, and is scarcer than Grayling.
Check here for the colour pattern of the underside of the frontwings:
http://www.lepiforum.de/lepiwiki.pl?Hipparchia_Semele
http://www.lepiforum.de/lepiwiki.pl?Hipparchia_Alcyone
Striped Grayling is the default species in the Algarve.