Good morning - I am not an electrician, but cannot seem to get a consistent answer to my question anywhere else and accordingly would appreciate advice from the knowledgeable members of this forum.

I have three phase power in my house, but recently installed a inverter for solar power which connects to one of the phases only. For various reasons I would prefer it if I can connect to all three phases, and it seems to me that the easiest (and cheapest) way to do it would be to combine the three phases into a single phase - I really don't have any need for three phase power, electricity load is not significant, have removed under floor heating in most of the rooms when I installed wood floors.
By asking around I have received the following feedback:
- Converting to single phase is easy - just join all three power wires into a single input wire (or bridge then 3 inputs on the DB board)
- a transformer, which is very expensive is required
- it cannot be done except by the municipality (when I live in a residential estate and is not directly connected to the municipal supply!!). The people who hold this opinion also tells me that I have to replace my meter - the current meter I have merely combines all three phases and is exactly the same meter as my neighbours, who don't have three phase power, have.

Please guys - what is the correct way of doing this (and for which I can get a CoC) - preferably a method which allows me to reverse the conversion in the unlikely scenario I require three phases in future