I am trying to find an extension / extensions that could handle the following promotion offer requirements.
Brand Promo - Buy 1 Full Price, Get x Discount of Further Products
Buy the first item of one Brand at full price and get a fixed discount amount) off every additional item of the same brand that are ordered at the same time.
Additional extra: Option to exclude certain products from those brands.
We need to identify customers who have bought products of a particular brand. Once customers have purchased x amount a one time discount code will be sent to the customer manually.
Once a customer has spent over £100 in a 6 month period admin is alerted of the customer id, the customer can then be manually sent a discount code. This would need to reset every 6 months.
I will try to suggest you 2 extensions for two of the 3 requirements mentioned by you.
1. Brand Promo - Buy 1 Full Price, Get x Discount of Further Products
For that you can try our Special promotions module. It will let you create the shopping cart price rule you need. You will need to create a complicated rule where all conditions true: brand is "the brand you need"; sku is not one of sku1,sku2,sku3, the latter is used to exclude particular products from promotions.
2. Customer Loyalty
It is possible to achieve what you need with our Loyalty Program extension. You will be able to create a rule which will be applied if a customer spent £100+ during latest 6 months. However, there is no feature to send an automatic email to the store admin with the client ID. But you can simplify that my setting up automatic discounts if the conditions you set up are met.