Checking the 0871 I found the same as Lompos - It's nothing to do with them - it's for the
TelevisionX channel.
Then the 0845 came up with
NOTHING as I suspect that it's short one digit !!
CCUK Ltd are in Liquidation according to Companies House
CCUK (London) Ltd, although mentioned on the Grumpier Old Men website are a mystery and that is the only mention of that address you gave.
And 5 minutes of Googling gave me the correct name of
Custom Computers UK Ltd (aka CCUK Ltd) and their website, which in turn gives you their contact number of
01582 599991
.
Let us know if this turns out to be them or not.
I have no idea where you got both those numbers from but someone really sold you a DUFFER !!