ok one question before I try all that.
currently I have one shipping rule active (which is needed - its to test if a customer ticks a box to collect instore rather then have it delivered)
that rule is:
Rule name: pickup
Trigger: IF Session variable pickup != 1
AND Based on session variable value
If the value of the session variable pickup is != a value of 1
Calculation: Flat rate 7
Now with the above rule (thats needed) how can I integrate your previous method?