The initials stand for High Performance Estate, created by fitting a Coupé front end and doors (with different window frames) to a saloon floorpan and finishing off with a hatchback rear section that pays homage to the Reliant Scimitar GTE. The result is a lot more stylish than that sounds, and you get the softer ride of the saloon with the lower seating position of the Coupé. In keeping with its superior intentions, only 1600 and 2000 engines were offered, with an optional 135bhp supercharged version of the two-litre for the last year of production.
info from Octane