Been thinking the maths over for two weeks, absence of computer preventing actual computation.
Got home, spent the last day checking the maths (and correcting it!), and then getting excel to do something useful with it.
Attached profile actually consists of only 160 data points (r, theta), but there's over 13,000 cells behind it. Possibly I've done it a lazy way, but it seemed the most straightforward. Would have helped if I could have written functions, but want to open it in OO too.
Just waiting to hear back from my cousin, hoping it is actually vaguely the right shape!
Will increase the data points to smooth it out if it is right.
edit - doh, google says I could have written those functions!