Site GoFor

I have recently moved into my home in Northern Ireland. Timber frame construction with Block work on outer skin. Majority of the blockwork is plastered with KRend and a portion finished with Natural Stone. When my builder was here he discussed with me the inclusion of prepend vents. The discussion concluded that in his view you don't need them and that some people put them in and others don't. He left them out. I got a little nervous before plastering and decided to include the below weep vents at 1200 below the interior floor level and under the sofit. I don't have anything between GF and FF and there is Red Rockwool Fire Barrier around the building at this level and up the corners. I was looking for some professional views on this. 1. Are the vents required? 2. What is the risk if they are not there? 3. Is what I have sufficient? 4. Are there any professional services that could come out and give me advice on this?