I did take some photos......and received a receipt from a member of staff

I made a complaint in March to Tesco about a croissant I bought from there. My 3 year old son was eating his croissant when he complained that there was something sharp in his mouth, I told him to spit it out. I then noticed a sharp piece of metal was in the other half of his croissont he was eating, luckily he had only scratched his tongue. I returned the croissant immediately to Tesco. I did not get a reply till last week, I was told that they had lost the croissant and apologised, in return forthere delay in replying I would receive an apology letter and a money card for £50. I was very disappointed and explained that my son could have swollowed that metal piece and that there could have been metal pieces in the other packs of croissants causing a person serious damage. Should I take this further or just except the apology? Regards Sash