Compaq no longer exists as an independent company. It was acquired by Hewlett-Packard (HP) in 2002 for US$25 billion. The Compaq brand was gradually phased out, and all operations were integrated into HP.
If you need to contact HP's UK headquarters:
HP Inc. UK Ltd.
Cain Road
Bracknell, Berkshire RG12 1HN
United Kingdom
For legacy Compaq product support, visit HP Support and select your product.