On holiday when I heard loud 'knocking/banging' sound from engine, immediately switched off, got recovery to take me to local (trusted) garage. They've said Adblue has leaked into DPF and engine? I'm genuinely terrified of what needs to be done, garage said 'it's a big job'! Anyone had similar issue?

What is it the big job they are going to have to do?

How much are they saying it could cost.

They said they think the Adblue had 'crystalised/hardened' and may have blocked DPF and damaged the engine? I didn't ask for a cost as it's got to be done and I do trust this garage. I'm dreading it though. Thank you for taking an interest, I love the car, I bought it 3 years ago, always have it serviced, a few mates had passed away suddenly and I thought 'treat yourself' so bought it.