The Block Exemption Regulation, where car manufacturers are no longer be able to make the car warranty conditional on having the oil changed, or other car services carried out, only in authorised garages, only applies to the new car warranty.
Other warranties may require the car to be serviced by the appropriate dealer network - I know the Toyota extended warranty requires this (see http://www.toyota.co.uk/cgi-bin/toyota/bv/generic_editorial.jsp?navRoot=toyota_1024_root&fullwidth=true&noLeftMenu=true&forceText=&edname=Owners-Warranty-Extended&zone=Zone+Ownership&id=Owners-Warranty-Extended) , and I would presume the same applies to the Toyota Approved Car warranty.
As it is a Toyota warranty, I would have thought the obvious people to ask about the warranty conditions would have been Toyota, rather than third parties.