Lexus Europe have decided to only offer hybrids (expect for the LC and Fs). 200t has been dropped across all models due to poor sales and their marketing decision to be all hybrid.
Year to date, Lexus GB has seen a market share increase, the first time for a few years, because of the decline in diesel sales and move towards hybrids. You could therefore argue their strategy is correct, they just don't cater for people who want semi high performance cars or manual transmissions which some people here seem to be upset about.
I'm not use the 450h package can fit in the RC. Even if it could it doesn't warrant the investment as the RC350 satisfies that space in the US, which is their main market.