can you see anybetter down the side of the house - Just a DIYer , but in the houses where i have worked , it can be above or below the airbricks , where is the door threshold maybe that helps.
The tiles , which i think you are laying tiles as previous post , once finished i have always thought of at the absoute minimum maybe a brick and half below the threshold , recommended is 150mm
I have had a houses where steps upto patio doors have been above DPC and garage above dpc had to take action to correct.
BUT Note - just a diyer