Freesat to replace old Sky Box

[oldaudi]

Some guidance please,

I've got a Sky Dish with HD Sky + in the main room and an old Sky (non sky+) in a room upstairs with one feed of coax to it from the dish.

Its an old box and the majority of channels that should be available are not, I get constant errors regarding signal strength even though the test options within the EPG show full strengthish and good signal and in my view the box is knackered.

Sky wants £100s plus fitting to replace it with a Sky HD box which Im not really interested in. Its connected to a Sony Panel with S-Video and Scart connections only and the Sky HD box only has HDMI now

Is it possible to replace the box with a FreeSat box so I just get the free to air, do I need to realign the dish at all?

Thanks.