£500 deposit for Permission to Market Property

TheRealTomTom

So my family and I am looking to move and have agreed a part-ex (after reading other stories here, we got offered a really good price compared to market value + £10,000 towards their upgrade brochure for fittings etc). 
Anyway, we have submitted the form to allow the developer to market the house while we are still living here. One of the points in the document states:

I confirm that I have been informed that a £500 security deposit against the property will be held upon completion by developer, which will be refunded within 28 working days from completion, providing a satisfactory vacation report is received from the agents. (If unsatisfactory, any costs incurred to developer will be deducted from this security deposit).

Now I wondered if anyone else had gone through this before. I get when you leave rented your security deposit can be hit for damages, but normally in a house move it is essentially sold as seen with the surveyors working out the kinks and negotiations. I am worried that they will just use that £500 as a tax essentially and claim XYZ is not up to standard. What kind of things might they look for? Should we be wary of? We are a family with 2 young kids, we keep the house as well as we can, but carpets are tired and walls could do with a paint, will they dock us for this?
I tried to get clarification from the developers sales team who replied with a vague email of "The extra £500 is refunded to you within 28 days after completion - once your PX property has been checked - no major issues or changes."  It is again, what do they class as a major issue that would normally be taken as sold as seen from the normal buying process?
Thanks

Blackbeard_of_Perranporth

Question. Do you want your new house and did you get a good price?
If yes, what’s the problem.

If no, turn your back on the deal!

davidmcn

Nothing to do with Mortgages, more one for the Housing Buying/Selling forum.

RelievedSheff

We didn't have a similar clause with David Wilson, The house was sold as seen.

Confused789

I am going through the same process. They told me it was just to ensure that you didn't leave junk in the house that they would have to clear out at a cost.