retention needed, cant sign contracts for house

hi, just looking for some advise please !

in the process of selling our house and buying another, purchaser went in last week to sign contracts, we then get phone call from our solicitor saying that their solicitor is looking for more information , only now !!!!

we built side extention and they want to see the planning permission notice, which we have so we sent it over straight away, we had alrealdy given the cert of compliance weeks ago. they then got back onto us saying that they now want some cert for the garden shed which we built when we bought the house 7 years ago, thats fine no problem we can get that aswell.

issue is, architect has just been up and it now turns out the porch that we built about 5 years ago is 12 inches to big. we will now have to apply for retention which is going to hold things up further, he said what normally happens is that the purchaser can still go ahead and sign and her solicitor will keep a bond untill planning goes through.

we need her to sign so we can sign for our new house, which is an executors sale so the house is vacant.

i am sick with worry, im just afraid people will pull out. can anybody offer some advise. can she go ahead and sign, is this a commom occurance, should we offer another deposit to the vendors of the house we are buying just to keep them happy.

everything else is all in order apart from the bloody porch which is only 12" out !!!!!!!

any advise greatly appreciated.

Where we live the planning permission process takes 12 weeks (now it may be shorter depending on where you live, numbers of applications etc). You have to submit maps/drawings/application form etc.
I'd be more worried about the sale of your house falling through (and you keeping those people happy) rather than the house you are buying.
If it's only the porch the buyers might not care that much and they might be happy to sign regardless, especially if they want the house and want to move it along. The worst that could happen is they would have to knock the porch or part of it down. A lot of people would just take that chance if they loved the house and wanted it badly.
You could ring your local planning office in the Co. council where you are and ask to speak to someone or make an appointment to speak to someone there about it. They may be able to assure you that retention will be granted, like or what is the best way to go about it...
You could always knock a few quid off the price of the house to get them to sign...(I am a buyer myself so I'm biased!). Like to make up for your lack of planning and organisation before selling your house...

They could sign if they want however what happens if retention is not given. Not a common occurrence but I'm sure they'll be advised of the same, and given there is little to no downside for them delaying signing, it is likely that is what will happen.

Personally 12 inches on a porch wouldn't bothere me, but no doubt the purchaser's solicitor will not agree particulary if they are doing the title for a bank.

OP would in any case be absolutely and completely mad to sign to purchase another house when he is only at contract stage on his own house. There are loads of houses out there and few buyers so OP doesn't need the stress of trying to put the cart before the horse.