Adam,

I'm not sure what spec the car was in when you bought it - I know it's Targa, Autosolo, endurance and 12 car legal but stage rallies are a step up - you need dated seats, harnesses and plumbed in extinguishers as well as a hand held and a fuel sampling valve (depending on when the car was log-booked with the Motorsport UK (if)). Nomex overalls and approved overalls are also a requirement - a substantial investment to go along with the slick tyres that you will end up buying (a set of fronts can last an event, maybe two). Before you take the plunge check that the car and your wallet are OK. I'd suggest marshalling on a few - the weekend after the Honington Targa is the Flying Fortress Stages in Northamptonshire. Ask for advice at club nights, maybe get a pre-scrutineering check from one of our local scrutineers. Also read the Motorsport UK rule book that comes with your licence.
Youy should also consider marshalling on the X Part endurance if you haven't yet entered.

Definitely enter the Targa - you could win in your car it's ideal for the format.