Like others, you're making things up as you go along. Why would he need to break-in to where he lived ?
It's from the police interview transcripts.
All Bamber's stuff will be at his cottage. He had lived there long enough. So why continually break into WHF?
If he needed access to WHF, he could ask Nevill, June, BW or JB.
He secretly broke in through windows for obvious reasons. Nevill & June had wisely not given him a key.