OK now I realise I don't understand, and am probably being a little dense here.

In my defence this is my first foray into Virtuemart, and I'm probably being a little over ambitious wanting to customise it from the get go.
The original fly page has {product_type}, post your modification that now shows as plain text in the product display in the shop.
I have created a product type 'herbal'
I have created a parameter named 'vegan' and the label is 'vegan'
Parameter type = 'text'
Possible values = 'Yes;No'
Default value = 'Yes'
Would you be so kind as to tell me what I should replace {product_type} with please?