While the property is on the market, there is no need to update the HIP. If the sale of your property stops and then starts again, you may have to compile a new HIP and provide up-to-date documents.
However, you can carry on using the same HIP without the need to update any of the documents where:
marketing stopped because an offer was accepted and the sale has fallen through (but remarketing must start within one year of the date when marketing first began or, if later, within 28 days of the sale falling through)
marketing has stopped for any other reason and the seller remarkets the property within one year of the date when marketing first began.
The effect of this is that the HIP has a shelf-life of at least 12 months for the seller.
ref -
http://www.direct.gov.uk/en/HomeAndCommunity/B uyingAndSellingYourHome/Homeinformationpacks/D G_171803