Thanks so much for your comprehensive advice Ron Bear.
I was definitely on the wrong track with where to start and now know exactly what to do.
Yes, as noted my 2km speed and 100m speed are quite close - I only really seem to have one speed at the moment and that's cruising!
Hopefully postage from the States isn't too long as I now can't wait to get in the pool and begin experimenting with my new toy.
Thanks again for your great advice - it is much appreciated.