Jon
i guess your probably at work at the moment, and time is tight but it would be well worth running over to KAIS, which as you say is only 30 mins from you and getting it set up to suit.
Even if you can't do it today, how about explaining the prob to Andy and even booking it in for crack of dawn tomorrow, i know this means missing the early part of the track day tomorrow BUT it may be better to do half a day with confidence, rather than a full day with doubts in your mind in view of last Sundays slip off (which i really believe is down to a combination of stone cold tyres and the masses of salt dumped on our roads of late).
KAIS are on 01942 896366 and speak to Andy (tell him Ron Williams sent you!) I did and he nearly had a fit