what size dish and satellite receiver are you using ??
bear in mind Sky UK/Ireland on 28.2E do frequently change Symbol Rates quite often
so you need to ensure you are checking flysat regular for up to date changes
Here =>
FLYSAT 28.2°E EAST
Strongest Transponder on 28.2E 10935 V 23000 DVB-S2 8PSK FEC 3/4 - 20db Signal - Channel 4 UK HD
Weakest Transponder on 28.2E 12090 V 29500 DVB-S2 QPSK FEC 8/9 - 14.3db Signal - Sky News Ireland
Have you tried doing a Blind Scan on your sat box ??
or are u just using a Sky Box if so which box ???
have you checked the dish for both clear line of sight and any Visible obstructions like trees blocking dish signals ?
Any Dect Phones present those are usually really good for picture Pixelation and reduced signals .
on a blind scan of 28.2 East you should be picking up 569 Channels if that is not the case then your dish is not aligned very well at all or your LNB Skew is not adjusted correctly .
Posting at least Some information would be very helpful if you can post back here again .....
Good luck !!