Glad you asked @MrMoo! To start, your initial thoughts on a local electrician is a great call. If the first attempt at installing and wiring did not yield the expected results, we do often recommend seeking an electrician for transformer installation, as this is considered high voltage.
In regards to the chime kit in use there, something powered by a low voltage of 8v, is likely not going to be rated for much higher than that. Proper functionality may not occur if adding it into the configuration with a 24v power supply or more. Check out our Chime Compatibility List to see if there is a better fitting chime for your setup.
Keep in mind, bypassing the chime kit and wiring directly to your transformer using the Pro Power Kit, and using one of our Chime devices, is another option. For any specific hardwired or hardware questions, these would be best answered by our support team, at 800-656-1918. I hope this helps! 