Channel 5 is still encrypted on Sky, but you've got a couple of options to access it.
If you want five to appear in the EPG on 105 you'll need a SKY card. FSFS(freesat from SKY) card's cost £20 which will also give you access to Fiver,Fiver+1,Five USA,Five USA+1 and Sky 3 which are all encrypted but free to view(FTV) with a card
You can add the "Freesat" un-encrypted(FTA) version without a viewing card,but it wont appear on the EPG on it's 105 slot. you access it by going into "services" then "other channels".
If you want to add it.....
Press "services" on the sky remote, then 4 for "system setup", then 4 for "add channels".
once on the "add channels" menu you need to add/edit the settings below by using the cursor/number buttons on the remote.....
Frequency(ghz) -10.773
Polarization - H
Symbol Rate- 22.0
FEC - 5/6
then scroll down, so "find channels" is highlighted in yellow and press select. Then when the channel list appears, highlight "Five" using the cursor buttons and press the yellow button to store the channel then press select.
to view it(as mentioned above, you need to go into "services" then press 7 for other channels.