Yes, sorry, meant to send that on via Rich after we chatted in Stafford. I've attached my suspension frequency calculator (I think - not tried attaching things before!). Should be fairly self explanatory - fields in black are for entering data; fields in orange are calculated. It uses some approximations of course but shouldn't be miles out. I've aimed for about 2Hz front and rear (which I've seen as recommended for sportscars on tarmac). Rear frequency is slightly higher than front to allow the rear to "catch up" with the front after they both hit a bump and so give a better ride by keeping the car level.
If anyone spots any errors/improvements then please let me know! I've made my current spring decision based on this and am so far pretty happy with it.
Suspension frequency calculator.zip