Hi
@Lyd. I'm an object lesson in how not to do it, so I hope my experience is useful. Mum was in her own home with no carers coming in. She thought she could manage but in fact things were getting dodgier by the day. She agreed that she would move nearer my brother (neither of us lived near her) into a sheltered flat. She'd seen a flat she liked and had agreed to the move. Before it became available two things happened. One it became obvious that even extra care sheltered accommodation wasn't going to be enough and two my brother became seriously ill. Sister in law and I cooked up a plan between us where she moved to a care home near me and we told her it was temporary because we'd got a buyer for her flat and her new place wasn't ready.
Mum was sort of OK with that. When the assessment happened I told her the assessors were two friends of mine who knew where my mum lived and had called me on the off-chance I was visiting when they happened to find themselves in the area. That went fine, and the home agreed to take her. Mum was charming to them and I don't think they knew what they had let themselves in for!
On the day I didn't say a lot, though I had said mum was moving nearer me temporarily. Mum got it in her head we were off on holiday (something we were supposed to be doing a month later) and I didn't disabuse her as it kept her happy in the taxi. Of course when we got there and she realised what the place was all hell let lose. The home were great, they took off their badges and cracked open the champagne and sort of got her to settle while I disappeared. For months afterwards she tried to escape, until her dementia moved on. Now she is more or less content, though she still wants to go home. Though it is her mum's home rather than her own she wants to go to.
Lessons learned. If possible have more than one of you on the day. I'd taken a suitcase there a couple of days before and her room was ready. If there had been two of us I think we could have kept things a lot calmer, as it was I was so stressed out I was handling it badly. With two of us we could have kept the chat up. Look we're visiting my friends you met a couple of weeks ago for longer. Secondly your MiL might not be happy, but I guess she isn't happy at home either and at least you know she will be safer in her new home, so try not to feel too much guilt. Thirdly it does get better though it might take a while