Quick, ish, hopefully, question 
So I'm looking into buying a house and fairly late in the stage the issue of a restrictive covenant has come to light (ex-council house).
The covenant basically states any extensions/outbuildings must have permission. The seller didn't follow this and hasn't had any issues for a number of years, and has offered to buy indemnity insurance (without me asking).
Now I'm half-thinking loft conversion, way down the line, which I believe would breach the covenant, and/or void the insurance (without permission at least, and not sure why they'd ever give me permission).
So after speaking to my solicitor last week I asked them to ask the seller to get retrospective consent rather than insurance. Which they've 'not agreed' to do.
So what to do, buy anyway and hope for the best, or put an ultimatum to the vendor of retrospective consent or '...' (dropped price? no sale?) We haven't exchanged yet but it's all in place to do so.
And obviously I've had an email from the solicitor earlier but not had a chance to speak and nothing will be done until Tuesday at the earliest, fun 4 days ahead...

So I'm looking into buying a house and fairly late in the stage the issue of a restrictive covenant has come to light (ex-council house).
The covenant basically states any extensions/outbuildings must have permission. The seller didn't follow this and hasn't had any issues for a number of years, and has offered to buy indemnity insurance (without me asking).
Now I'm half-thinking loft conversion, way down the line, which I believe would breach the covenant, and/or void the insurance (without permission at least, and not sure why they'd ever give me permission).
So after speaking to my solicitor last week I asked them to ask the seller to get retrospective consent rather than insurance. Which they've 'not agreed' to do.
So what to do, buy anyway and hope for the best, or put an ultimatum to the vendor of retrospective consent or '...' (dropped price? no sale?) We haven't exchanged yet but it's all in place to do so.
And obviously I've had an email from the solicitor earlier but not had a chance to speak and nothing will be done until Tuesday at the earliest, fun 4 days ahead...