Sol has sent proof of ID back to wrong address

[Doingitover]

Just as the title states really. I had to send proof of ID docs off to solicitor for a remortgage. Docs included my original passport ( had to be the original) bank statements and a utility bill. I started to get a bit nervy about a month ago because they hadn't yet been returned so I started to chase. Originally I was told that they had been returned but they couldn't find the tracking number. So I had days of waiting for a manager to call me back.
Today I've finally had a call back and they have admitted that It looks like they have mistakenly taken 2 addresses and merged them into 1 address and sent the docs out to an address that obviously doesn't exist!
I've been told the post office will end up returning them back to sender once the error has been noticed!!
Basically I'm being told to chill out its no big deal.
However even I know a fraudster doesn't need much to obtain credit.
What do I do???
Solicitor isn't worried, thinks I'm overreacting. Ive asked for a copy of the firms complaint procedure but in the meantime someone could be using the docs to apply for all kinds. And even if that doesn't happen I want my passport back.
I'm in the middle of a remortgage I really want to tell them to shove it. But my mortgage advisor has suggested against cancelling the instruction as its late in the game and anyway I wouldn't be able to prove my ID to a new company.
Does anyone have any advice on what I can or what I should be doing?

Complain via their procedure, if not satisfied, go to the Ombudsman.

Why were you posting documents? Are you using someone not local to you?

It's a data protection breach and reportable to ICO. Ask them about that and see what they say!

How is someone's physical passport going to the wrong address a data breach?

I'd be more interested in how compliant their moneylaundering procedures are, if OP has never met them. She herself could be anyone!

This is the second property I've remortgaged in 12 months. The first solicitor had exactly the same ID procedure so I had no reason to question the process. Yep the property/solicitor is in another city but I would have posted even if same city. (8 week old baby) As for the solicitor returning the docs by post I wouldn't even think to question it. The post isn't the issue. The issue is the process they have in place that has allowed such a mistake to happen.
I've asked the solicitor to confirm exactly what was in the envelope. Im still unsure if it was just my passport or all of my ID docs (copies of bills, bank statements) they also still haven't told me if the item was tracked.
They just don't seem to have any urgency about getting this resolved!
I don't really understand the money laundering issue?
I really just want to protect myself in the event of fraud.

personal.help.royalmail.com/app/answers/detail/a_id/7173/session/L2F2LzEvdGltZS8xNDc0MzU1OTM5L3NpZC83cF9WejRfbQ%3D%3D

It could take a while - if there is no return address on the outside the letter will be in Belfast.

I don't think I would be happy about the passive attitude - the solicitor should be informing the Royal Mail about their mistake and about the contents. Perhaps you should tell them you will be holding them responsible for any consequences of identity theft.

Thanks CD I'll have a look at the link. I think you're right though, this isn't going to have a quick resolution.
The solicitor still hasn't confirmed what was in the envelope. I'm going to try and research credit companies today to see if I can flag the issue.
I have however had an email from the solicitors admin dept chasing up an old mortgage account number. I really want to tell them not to bother doing anything else about the mortgage as I don't trust them but I'm presuming they will still bill me for full amount of services if I switched. So I would end up with 2 fees