Dear 4FootyFans,
The easiest way to exclude a shipping method/rate for certain products is to use a hidden category. With the advanced shipping by Rules plugin you can then check the list of categories for that disallowed category:
Name="Low rate"; 1<=Weight<=100; 1<=Amount<=74.99; Condition=contains_none(Categories, 1234); Shipping=....
Name="Higher rater, category 1234 is in the cart"; 1<=Weight<=100; 1<=Amount<=74.99; Condition=contains_none(Categories, 1234); Shipping=....
The ID of the excluded category is 1234 in this example. The "Condition=" is there to indicate to the plugin that this term is a condition. The plugin usually auto-detects which part of a rule is a condition by checking for the existence of comparison operators like <, ==, etc. If the rule part would only be "contains_none(...)", then the plugin would miss to detect this as a condition, so we have to explicitly tell it that this is a condition.
Best regards,
Reinhold