house sitting-bills etc

[stressedouttumbleweed]

We are buying a house from a relative. It's been delayed slightly due to some issues with the deeds but our sale is completing before we'll be able to exchange on it.
The property is empty and our relative is happy for us to move in. We won't be renting as they have a mortgage and don't want to go through all the hoops for permission to let etc etc. We've arranged our house insurance cover to go to new property when we complete on this.
Can we put the council tax, electricity etc into our names when we move in, or could this be an issue?
Are there any risks to either of us we haven't thought about? (both parties wish to continue with the sale, it's just these delays were unforeseen and our buyers put far too much pressure on us, and we need to move to the new location for employment etc)

How long is the delay? It doesn't seem worth it to me. I was selling g a house and a friend moved in temporarily. I kept everything in my name and she just paid for the time she was there. Surely we are not so regulated that you can't help out a friend or relative with housing. But as she is not informing her mortgage company putting things in your name may provide 'proof' that she broke her contract, if such a clause exists. But I would have thought as the house os insured and occupied and mortgage us still being paid, it is fine. You are not a 'tenant' in the usual sense.

@Changingwiththetimes We're not sure how long the delay will be. We are hoping not too long but seems it comes down to solicitors, banks and the land registry all playing nicely together. It could be up to a couple of months (hopefully not past end of June as we really don't want the stamp duty bill!)
Happy to just pay the bills but wondering if council tax would be an issue (they have moved into another home so presumably paying council tax there and this house being listed as unoccupied) It is the house we will be buying. We will likely give them money towards mortgage payments but not "officially"

Where I live you still have to pay council tax even if a property is empty.
I have a friend camping out in a flat I'm selling (not to him). Just a couple weeks but it's not official, there's no agreement and I'm still paying the council tax.
What do your relatives say? Surely it is up to them.

So you're moving into the property that you're buying before the sale has completed?
If I've understood that right then I think you should offer to pay the bills seeing as your relative is effectively covering your "rent" until the sale completes. If they have declared it unoccupied on the council tax then you definitely need to pick this up.

@emmathedilemma yes we're moving in before sale has completed.
We are very happy to cover the bills, we're just wondering if we should transfer them into our names before completion... We've already sorted home insurance to start the date we move in.

There's little risk to you, your relative may be creating a tenancy by mistake. Are the insurers happy with this?