@KirstyReader The route taken to bring broadband to the outside of your property is not determined by Sky, or any other ISP if you are tempted to consider trying a different provider.
In most circumstances Openreach (or in some limited cases, City Fibre) provide the network infrastructure to the outside of your property, and it'll be their decision as to whether overhead wires are the only option.
The one exception is if you are in an area where either Virgin Media or a newer Altnet broadband provider have laid their own underground cable infrastructure in your area.
If your service hasn't yet been started you may be able to cancel without penalty by contacting Sky. However you will, unfortunately, have to do your own research to see whether an alternative provider is available in your area who are in a position to use their own underground infrastructure.
Failing this, there is also the possibility of other wireless broadband options, such as satellite or 4g/5g, but again you'll need to research availability.
