I once wrote a cheque for a drain cleaning company using my son's cheque book. Totally different signature. My son's bank paid it and even sent him a copy of it when he queried it! I did do it in error- I thought I could write a cheque without my glasses. I can't!!
Sorry, I should have said I was the cash manger at a FTSE 100 company and I banked all sorts of nonsense cheques over the years - sometimes it was queried, sometimes not.
I would actually try and bank it if the figures are correct in the box - after all some people would say 'twelve hundred pounds' rather than one thousand, two hundred and 'one two hundred' is not that different to twelve hundred is it?