What i would do maz, is straight away get into getting the RR roadworthy, nevermind getting it to the courses you wont be allowed to enter or drive legally down any tracks without it being taxed and tested, and insured.
What i would do is get it MOT'd. See the report as likely it WILL fail, then find somewhere that will get it through the MOT as cheaply as possible.
When you have an MOT for it you can insure it, and then renew the tax when its due.
Once the RR is fully roadworthy i would sell the vectra and then use the RR full time. The RR will be a much nicer car to drive and you wont have the huge expense of running two vehicles at once which is pointless if you are not doing huge miles. The saving from running two cars will more than pay for the extra fuel the V8 uses.