Companies House are located in London, Cardiff and Edinburgh. Their Contact Centre is in Cardiff.
For Companies House, Crown Way. Maindy,Cardiff, CF14 3UZ
192.com gives:
029 2038 8588
029 2038 0900 (fax)
Their website
http://www.companieshouse.gov.uk/contact/contactUs.shtml gives 0870 33 33 636 as the number for the Contact Centre and so does the recorded message if one dials 029 2038 8588
The recorded message also gives some other numbers:
029 2038 8111 (DWP and shared services)
029 2038 1248 (Job Centre)
029 2038 0625 (DTI)
029 2038 1300 (Official Receiver)
They may all be in the same government building.
Searching 192.com for their other offices:
for London the 0870 3333 636 number comes up. However for Edinburgh geographical numbers are given:
0131 535 5800
0131 535 5820 (fax)
Suggest you try the Edinburgh number, may be they can transfer you or deal with your query. Alternatively try 029 2038 8111 and see if they will transfer you.
Others Forum members with a "free" phone package may try to track down the geographical Cardiff number. The starting point may be the 029 2038 0900 fax number which does work.