Post structural survey - mortgage question?

squarehead94

Hi all.
Currently going through an app with nationwide. Long story short the house I'm buying needed a structural report on an old chimney breast. I can copy & paste the instructions from the report if necessary.

Report states approx cost to repair is £1500 + VAT. Valuation company mortgage co used come back and funnily enough, valued it at my purchase price (which was a bit on the cheap side) and the current value at exactly £1800 below the value.

Anyway, I'm just wondering, should I be accepted, what the likely scenario would be? 
Would they still offer the full loan amount?
Would they offer a retention amount with the difference being released following completion of works?
Could I negotiate with seller, purchase for £1800 less and not have to immediately do any repair works? So I am not time bound to complete them as we would like to complete and move in ASAP and I can worry about sorting the chimney at a later date.

Thanks in advance