The URL you gave is invalid. This one is correct:
http://www.uk.experian.com/e-help/motor/

You can access that service online. Why don't you do that, or is there a problem that you need to discuss with customer services?

Call Business Support Investigations for queries on a search you have carried out
     Telephone:      0870 527 5145 (select option 1)
     Fax:      0115 976 8376
     Monday - Friday:      09:00 - 17:30
     Saturday:      09:00 - 13:00

Call Experian Automotive Installation Support for queries about installation
     Telephone:      0870 527 5145 (select option 2 then option 1)
     Fax:      0115 976 8378
     Monday - Friday:      09:00 - 17:00

The fax number is in Nottingham. Notice also they tell you to select different options. It might be worth calling their Nottingham office and asking to be put through:

TALBOT HOUSE
TALBOT STREET
NOTTINGHAM
NG801TH
0115 941 0888
0115 934 4905 fax

Alternatively, Googling came up with these 0115 976 numbers:

0115 976 8939 (business services)
0115 976 8448 (Lambert House address)
0115 976 8747 (may just be a recorded message, worth a try)

Google for:
experian "0115 976"
and you'll probably find more numbers.

When trying these numbers, do so before 5pm as that's when they close. If you find anything useful, do report it here and add it to the database on this site!

0115 934 4266 WORKS
1715hrs 16 Aug 06