OK, found a way to do it (not sure if it's the best though):
1. Turn off all Free shipping modules.
2. Still in 'Shipping Modules', use 'Table Rate' to set up a delivery price of £5 if order total is up to £65, £0 if order total is £65 – £10,000 [65:5.00,10000:0.00]
3. Keep original cloned Flat rate for Express delivery

This works for me, now depending on order toal you see either £5 Standard / £7.95 Express; or £0.00 Standard / £7.95 Express.

Saves touching any code - a big plus for me!!

Though still have problem that when you go to the checkout (step 1 of 3) neither radio button is selected - it does force you to make a choice but I still thinks it's confusing.