Soldato
That seems very odd - if you suspect someone of money laundering you are not supposed to tell anyone as it could be classed as tipping off.
The main source of my deposit was a family gift. The mortgage company asked for a letter from the donor saying it wasn't a loan, which the solicitor had a copy of. 2 weeks before completion the solicitor decided they wanted another letter saying the same thing because it wasn't in their standard form. Could be something similar here.
There is probably nothing wrong but its just annoying that we could have exchanged as early as 18th September and now they decided to do further checks. Hopefully its just because they couldn't be bothered to finish the paperwork on Friday afternoon and will just do it Monday morning.