Depending on the specific Powerline adapters used and the homes internal wiring, many get no problems at all from their use.
My homes electrical wiring and a power socket ran parallel up the wall to the incoming OpenReach line.
Powerlines caused very high FEC/Rtx_tx on my line when in use.
Removing that power socket and its wiring cured all issues. Using the Powerlines now has absolutely zero impact on my xDSL.
A number of others also have success using them but it does indeed cause considerable issues for many.
I've also seen comments that 1 brand caused issues with their broadband but a set of BT powerlines worked flawlessly.
What you want to achieve should work though. Perhaps monitor the line when turning on the adapters to see if it has any negative effect.