Survey - Drainage problem.. What to do next?

scope

I've just had my home buyer survey back, and the following has been brought up as an action:

DRAINAGE SYSTEM: "The lids to these inspection chambers were lifted Significant blockages were identified which could indicate a defective system

ACTION: You are advised to instruct a specialist drainage contractors to test the drains and report upon their condution together with a quotation for any repair works required.

This is a fairly new property (5-6 years) on a new estate.

How much would such an inspection cost? Would they need to use CCTV to find out whats causing this?

I am keen to have this checked before we exchange, as it can cost anything from a hundred pounds to thousands (I guess), I will then try to reduce the purchase price of the house Im buying.

silvercar

Either get a drains test done, which will include CCTV if the blockage isn't obvious or ask the vendors, through solicitors, if they have had drain problems. If they have, tell them to sort it. If they haven't make sure you take drains insurance out when you buy, either included in your buildings insurance or as an add on to your other service cover (i think British Gas charge an extra £3 a month for plumbing cover.)

scope

I have spoken to both the solicitor and estate agent (who in turn contacted the vendor) and it seems they are going to get it sorted.. I have asked for a report from the drainage specialist to make sure its all good.

For anybody interested, I have rang around a bit and it seems the going price for a CCTV survey (with unblocking blockage) is about £200..