Retrofitting Insulation and Double Glazing
Please see this government guide to retrofitting internal wall insulation which may help if you are considering contracting a firm to do this.
Solar panels for practices
You will need to check with your mortgage provider if you own your own premises, and if the premises are rented, you will need to arrange this via the owners of the building. There are community interest companies in several cities and regions which are keen to put solar panels on public buildings including GP surgeries through deals which will reduce your bills and generate electricity. Community Energy England may be able to link you up.
Air Source Heat Pumps
Air source heat pumps are another option for providing renewable energy to your building. Which have a guide on air source heat pumps.