Finding cabinet info for unbundled lines (e.g. TalkTalk)

BT's line checker at dslchecker.bt.com does a great job of telling you via which roadside cabinet your phone line is routed - as long as your line isn't unbundled. I'm trying to find out the cabinet number for a TalkTalk line, as BT's checker has no information for this particular phone number. I've trawled the TalkTalk website, and spoken to their tech support line, but they can't tell me this info. As the infrastructure surely still "belongs" to Openreach at some level, does anyone know how I can go about finding out the cabinet number for this line?
The exchange is Chipping Sodbury (SSCSY) in South Gloucestershire.

Use the address checker http://www.dslchecker.bt.com/adsl/ADSLChecker.addres...

Well, blown me down, I never knew that was there. The info that it's produced has confirmed my assumptions about the routing of the line - so thanks very much!

A useful tip about that address lookup. If you just enter a postcode on that page and submit it, it gives you a drop down list of all addresses in that postcode. Often you find more than one cabinet.

Never use the pure postcode option. That is very unreliable.

Weirdly when using both phone number search and full address search i get slightly different eetimated speeds. Dunno why that is?

They're just an estimate.

Telephone line is more accurate as Openreach systems will be able to test the actual line to get its length and characteristics to come up with a more accurate estimated speed whereas address will be based on far less facts about the actual physical line to the property.