I have to disagree with you jake. It is not group 10, there is a typo in Parkers. If you go onto the Association of British Insurers Website (
http://www.abi.org.uk/carinsurance/search.asp) and search for
Ibiza, the correct list for the GT, GTE, GTi & Cupra series are:
Model..................................Start Year...End Year.......Group........Engine
IBIZA GT.................................1993.............1995.............10.............1984cc
IBIZA GTE ..............................1994.............1994.............10..............1984cc
IBIZA GT 16V...........................1994.............1996.............12.............1781cc
IBIZA GTI................................1996.............1997.............10.............1984cc
IBIZA GTI 16V.........................1996.............1998.............14.............1984cc
IBIZA GTI CUPRA SPORT..........1997.............1999.............11.............1984cc
IBIZA GTI CUPRA SPORT 16V...1997.............1999.............14.............1984cc
So as you can see, the only one where the Cupra was in a higher group than its GT or GTi cousin was the 8v Cupra Sport.
This is based upon the ABI website, but obviously individual insurers can choose to interpret this anyway they want to.