It does seem unbelievable that plod turn up for that, but when my DS was threatened physically in the street last night, by a man with a record of violent offences including against a pregnant woman, there were no officers available. I'm not disbelieving you, btw.
And to tell you that accepting a caution doesn't matter...
I think I'd actually contact my local MP and kick up stink, tbh. Not sure they can get this removed from your record, and with luck it won't affect your employment prospects (as llareggub says), but you need to get the news out that this is bloody serious.