You need an rf modulator like this
If you purchased the current modulator from Sky you can keep it and use it as you own it. If it was part of the install and was returned with their decoder then you can probably purchase a new one from Sky.
I think I own it so how do you know what number to have it on? Thanks
Doesn't matter as long as it doesn't conflict with a Freeview UHF channel which isn't a problem if you are Satellite only. Just tune the TVs to that channel number. If you have it and own it and it was working OK with Sky then all you need to do is plug in the A/V leads from the S8200 instead of the Sky A/V leads. Your TVs should already be tuned to the number on the modulator display unless you changed the channel.
If you don't get an answer here - you may like to try Geekzone There are many people there who may be able to help you.
Excellent thanks. All working again!