think you'd need track day tyres to make this a worthwhile proposition, and not many people have the luxury of a spare set of those.
£475 just for the track action. so ~ 23 laps compared to paying per lap on TF day. Don't think i'd be happy doing that many laps in one day on the ring!
also should someone crash, and it closes the track, then you're still exposed to potentially reduced track time (and making the £475 VFM)
at least with TF you can carry your lap credits to any other TF day in the year.
Have you signed up for this then John??