Thank you all for the really helpful comments.
We visited many of the places mentioned above and liked more or less everywhere.
I need to remind myself that part of this move is about being closer to grandchildren and so even though we loved Forres, Findhorn and the coast up there they are probably just outside my travel journey of about an hour and a half at most from Aberdeen and in that case Huntly is in the lead.
The other thing we noticed apart from the spectacular countryside (don’t let on that East is just as wonderful as west) was that when estate agents call somewhere rural the English translation would be remote.
We looked at a tiny cottage high up in the cabrach and the views were amazing and just on that quick visit we saw wonderful wildlife but it did feel a tinge remote.
Still looking forward to this adventure late in life
Some things about travel. The road between Inverness and Aberdeen is fairly well known as being horrible and that will be relevant to you whether you are looking at somewhere like Forres, or closer like Huntly. If you are the type who insists on driving. The alternative is the rail line, which at present is rather slow and infrequent. However - it may be useful to know that various improvements to this are in the pipeline, and of course you can never be certain that these projects will be delivered in full or in time, but it does mean that the rail journey from Forres to Aberdeen, currently just over your 1h30 limit, may in the near-ish future become easier and faster.
Aberdeen to Inverness rail improvements
I grew up in the highlands and am aware of our 'rural' tending to be equivalent to the home counties' 'remote'.
If you want community then you should give some thought to the consequences of the isolated cottage option. It doesn't mean there is no community - scattered settlements are the norm in the north of Scotland (although, in the northeast, the densely packed small village is much more common than in the northwest) and people will still tend to know the people living nearby
if they want to but there's not the same opportunity to run into people at the local shop or pub, either of which might be 5 or 20 miles away and only accessible by car.
On the subject of old age, it's not just that if you become in need of care, people have to be able to get to you. You can be fairly healthy but something can happen that stops you from being able to drive. You might be perfectly able to walk a couple of miles and look after yourself but you then become totally reliant on others for transport, shopping, etc. I've seen this happen to people including family members. People easily become isolated.
Make sure you spend some time in the area during winter before making any final decisions. In my opinion, the main issue with winter, and I think the thing that people often underestimate, is not necessarily the rain or the cold but the light. Think about whether that might affect you. If you already find december/january a bit grim to get through in Hertfordshire then you might struggle in Aberdeenshire. Just be aware of this, that's all. And think about it when looking at houses. Where I grew up there's a period where the house doesn't see direct sunlight for several weeks because the sun doesn't make it above the hill opposite. If I ever move back to the highlands I'll make sure I find somewhere that gets all the winter sunlight it can get.
