I suspect MG are looking to grow their market share, so low cost servicing is part of that strategy, plus there is not a lot to service on an electric car so you could argue it's even more of a rip-off than Lexus.
I do agree Lexus service cost are high, but unfortunately seems the industry norm for the UK at least. I find most independents pretty poor, so there could be a market opportunity for a decent chain of independents.