I've just clicked what thread this is.
I read it last night, and there was a lot of uninformed comments. For example, whilst it's best practice to leave a liaison officer with a family, it's not necessary and depending on the crime and Force involved, may not happen at the arrest stage. Seizing just the devices listed on the warrant would be standard, if they know what they are looking for, getting a warrant to seize specific goods is much easier than getting a warrant to search a house.
OP is not married to her DP, if I'm remembering rightly, so has no right to information - and again, if the crime and current thinking means the police are only interested in him at this time, they wouldn't speak to her or introduce themselves.
It doesn't sound like they broke in and arrested him. It wasn't a raid. It sounds like two or three policepeople visited OP's DP at home, and asked him to accompany them to the station, along with requesting that the provide access to the devices listed in the warrant. If he chose to accompany them, nothing more would be necessary.
I'm not 100% on this bit, but I'm not sure a phone call would be necessary if he was arrested from home and someone was there and aware of his location. The usual purpose is to inform someone of where you are. He would be allowed to call a solicitor, but most people use the duty solicitor.
There was a big pile on of people who spoke with authority. They may be educated from police TV, or second-hand through a friend or partner in the police, or guessing. They may know the procedures of a specific force well, but not general policy. Once you have a lot of people throwing questions and accusations, the thread becomes unbelievable.
It was a definite example of a thread where everyone wanted to say they called troll first. I understand why, with the very similar troll thread recently, but it makes the site unusable. Any actual advice was buried amongst people trying to pick holes.
If it was a troll, fair enough. If it wasn't, though, there was someone at the end of the computer who wanted to use MN for support and got absolutely torn apart for not knowing nine million details - when knowing everything just after the arrest would have been far more suspicious, especially in troll terms!
I may be taking this slightly personally as I was accused of trolling after the Christmas dinner thread... and I absolutely wasn't. It hurt. It shouldn't - it's the internet, etc - but it did, anyway.
OP - Is your DP home?