Hi londolozi
Opening all GB and IRE racing markets at one time and connecting them all to Excel will be an enormous load on the system. If you are going to do that, it will be better to do them in batches according to start time.
If you are wanting to identify markets where there are withdrawn runners, why not simply use the condition:
markets number of withdrawn runners is greater than 0
or better still use the market locator property:
markets number of withdrawn runners is greater than 0