There are many banks in Bulgaria and the choice is yours.
It is not currently possible to open a Bulgarian bank account from the UK so I would recommend that you open one on your next trip.
If you are are signing a power of attorney for your solicitor to act on your behalf they can set up utilities and open a bank account for you.
We opted for DSK Bank. We contacted a few banks to help us decide what was right for us. DSK had a friendly English speaking (we have not yet mastered the Bulgarian language) call centre and the operators were were very helpful. When arriving at DSK bank in Bulgaria (Varna) to open an account the spoken English was limited but the lady was still very helpful and patient. DSK do charge a monthly fee. I have since discovered that you have to authorise direct debits and transfer internet in a DSK branch. This is worth mentioning at the time of opening your account, especially if you are using your home for holidays.
You can relax now as you have a bit more time to set up your electricity, i have not done this as yet but here is a useful link:
Energo Pro – You will need your passport and house documents which will have to be original documents.
Telephone and Internet & TV
Are readily available in Bulgarian villages but most websites are only available in Bulgarian. If you pop into a shop whilst in town there are options available. If you are to be using your new property as a holiday home there are packages available which you pay the initial installation fee and use on a pay as you go basis for a minimum of 1 month.
There are a lot of TV programmes and films in English with Bulgarian subtitles. You can use a UK sky box but you will need a 1.5m satellite dish.