Combining 2 products

Is it pizza that you are trying to sell, or something else?
I suspect what you want may be able to be achieved using WooCommerce itself but need a bit more context to be able to suggest anything.

I am selling firepits, we have basic designs and we allow the clients to combine 2. ie: 1 x Harley Davidson and 1 x ACDC, but not adjusting the price at all. Most prob using the most expensive price hopefully !!
Does that help any ?

Sounds like you are looking for Product Bundles: https://woocommerce.com/products/product-bundles/

I tried Product Bundles and it isn’t what I am looking for, nearly, but not perfect.
I want to be able to have a product called 1/2 and 1/2 .. and then the client picks from all the products, from a pull down ( like attributes or variations ) but I don’t want to be manually putting it in every time I have new products, so it needs to do it automagically.

Ahh, gotcha. So Composite Products might be what you need then: https://woocommerce.com/products/composite-products/

You can set up two components that allow the user to select a product from a category: https://cld.wthms.co/1ikuh/1RX90hQS. That way you won’t need to add new products every time, they will automatically appear if they are in the category.