Find a specifc entry in an array with multiple entries of the key field

Hi everyone,

I have a list of services for machines. The information for one service forms one entry of the spreadsheet.

The machine has a unique serial number which is on each service entry.

Each service entry has a type A, B, C or D.

The service type required for a machine is determined by its contract type.

I am working in another table which is a list of machines but i do not have the contract type and want to determine it from the data held in the service history file, which helpfully, also doesn't have the Contract Type!

So i need a lookup that will:

If the Machine has EVER had a service of type "A" then it is Contract Type 1
If the Machine has NEVER had a service type of "A" then it is Contract Type 2


Could anyone help me with a formula to achieve this? I've attached a basic example.

Thanks in advance for your help.