At random my clubman has a rough start, sputtering and spitting before it starts

What is your question?

Random problem. I just had spark plugs and ignition coils replaced. It had 9 error codes in computer but it still spits and sputters with engine light going on and off before it finally engages. The mechanic says it's because its old. I disagree, car has only 48,000 miles. Now what