A small hole drilled surely won't cause any major crack. Add rawl plugs and screw in temporary metal cup hooks, that can be removed after Christmas.Issue is, the cowboy developers have rendered the front on top of what I suspect was pebble dash before.
The only reason I think this is the sides are pebble dash and the front render seems very thick. It's solid as hell but I don't want to risk drilling into in case I start damage that then leads to more.