Everything worked out just fine
I was initially hesitant given I was unable to find any reviews and the reviews of the American counterpart Sirva being less than flattering. However, everything was handled professionally, and in the end all my goods were delivered door to door on time in an international move across new Brexit borders.
Note that iMove handles only the organisation of the move but not the removal and storage itself, for which other companies are subcontracted, so there is some trust needed in the subcontracted companies which iMove says are carefully selected.
In my case, there was an issue with delivery dates because the company handling the move between countries said they could only do a date that was weeks too early. However, a solution was found with additional storage without extra cost in the destination country ensuring delivery at a suitable date.
The claims reimbursement process for some smaller damages to moved items worked without issues, but took 2.5 months.
All in all, it was rather pricey, but a good all inclusive option for a larger house move between countries.