OK, bearing in mind that I am not an expert, this is how I see it.
You have some evidence to support the building have been used residentially in the past, but you also have to consider whether that was "incidental to the use of the house" or as a separate dwelling (it makes a difference). There are now several routes you can take ...
1) You just go ahead, "do up" the place and start using it. The council will almost certainly find out, especially if you use it for a business (holiday cottage). They will almost certainly claim it's not got the right permissions and is therefore illegal.
At this point, you have spend the money on the building and starting the business - you may win and get to carry on using it, you may lose and have to stop (thus wasting your money). From the sound of things, it's possible you may have a precedent for legal use "incidental to use of the main house" - but not for it's use as a separate dwelling.
1b) You could go down the above route, but only spending the very bare minimum (make it habitable, but market it as "with character" !) - test the waters and accept that if you lose then you've not lost a lot.
2) You could decide that the whole thing is not worth the hassle and forget about it.
3) You could apply for a Certificate of Lawfulness for an Existing Use or Development or a Lawful Development Certificate.
By doing this, you get to present the evidence and argue over it before spending any significant amount of money. If you lose, then you haven't spent a load of cash doing up the building only to be told later that you can't use it. If you win then you can spend the cash with a certificate that states you can use it - and the planners can't then stop you.
On option 3, I have a feeling that you need to consider the current state of the building. If you apply for a certificate, and they come to look at it, and see that there's no sanitary facilities - they could argue that it isn't a standalone dwelling ("it's clearly not had a bathroom for many years, can't have been a dwelling"). You'd then be on the back foot having to show that the lack of facilities was a recent and temporary thing - and hence didn't affect it's legal status as a property.
So I suspect it may be worth spending a small amount to get the building to a state where such arguments can't be used. Ie, get it to the state where it's got everything required to be a dwelling, even it it's still well in need of significant modernisation. Also consider that if the rest of the building is a rough shed, but it's got a shiny new bathroom, then that's going to prompt questions - so "a lick of paint" so the rest doesn't look too bad might be in order.
But I would suggest listening to those who know about, and have experience with, such matters.
You have some evidence to support the building have been used residentially in the past, but you also have to consider whether that was "incidental to the use of the house" or as a separate dwelling (it makes a difference). There are now several routes you can take ...
1) You just go ahead, "do up" the place and start using it. The council will almost certainly find out, especially if you use it for a business (holiday cottage). They will almost certainly claim it's not got the right permissions and is therefore illegal.
At this point, you have spend the money on the building and starting the business - you may win and get to carry on using it, you may lose and have to stop (thus wasting your money). From the sound of things, it's possible you may have a precedent for legal use "incidental to use of the main house" - but not for it's use as a separate dwelling.
1b) You could go down the above route, but only spending the very bare minimum (make it habitable, but market it as "with character" !) - test the waters and accept that if you lose then you've not lost a lot.
2) You could decide that the whole thing is not worth the hassle and forget about it.
3) You could apply for a Certificate of Lawfulness for an Existing Use or Development or a Lawful Development Certificate.
By doing this, you get to present the evidence and argue over it before spending any significant amount of money. If you lose, then you haven't spent a load of cash doing up the building only to be told later that you can't use it. If you win then you can spend the cash with a certificate that states you can use it - and the planners can't then stop you.
On option 3, I have a feeling that you need to consider the current state of the building. If you apply for a certificate, and they come to look at it, and see that there's no sanitary facilities - they could argue that it isn't a standalone dwelling ("it's clearly not had a bathroom for many years, can't have been a dwelling"). You'd then be on the back foot having to show that the lack of facilities was a recent and temporary thing - and hence didn't affect it's legal status as a property.
So I suspect it may be worth spending a small amount to get the building to a state where such arguments can't be used. Ie, get it to the state where it's got everything required to be a dwelling, even it it's still well in need of significant modernisation. Also consider that if the rest of the building is a rough shed, but it's got a shiny new bathroom, then that's going to prompt questions - so "a lick of paint" so the rest doesn't look too bad might be in order.
But I would suggest listening to those who know about, and have experience with, such matters.
