I understand that you want to know where to send a SlingCatcher to be repaired, since you are in the UK.
I recommend you to check the following link and scroll all the way down on the page. Make sure to reach the information for UK and check the available support options.
Sling Media Paid Support Offerings
If by any chance you do not know the local tech support contact phone number, it is (020) 7294 0157.