Very difficult to help someone choose an ISP, but if you look at this site you will be able to compare all the Broadband providers for yourself. click here when you get to the site, look on the left of page and you will see a link to "Compare". You can then select as many ISP's as you wish, and compare users feedback.
When you receive you B/B kit, it will contain two filters. With your set up, you may only need to use one. Plug the filter into your main Phone socket, then the Telephone and Sky into the phone side of the filter, Your broadband cable will plug into the ADSL side of the filter and direct to your new Broadband modem. Please post back if you need more advice on the setting up of the broadband, one of the forum members will assist you. j.