Hi Jsmosby. Firstly, many thanks for replying! After 50+ views I was beginning to wonder if the pictures I'd posted were showing!

Cleaned with hot soapy water and a scrubbing brush, then a wire brush attachment on my electric pillar drill. We were wary of unexploded ordnance and did find one or two bits that were suspect, but all proved to be harmless. When you put large amounts of ordnance in a hole and blow it up, there is little chance of anything live surviving.