At the top end of the market the amount of money involved means it's often more economical to focus on maximising occupation, rather than minimising initial costs. My apartment, for example, is worth around £1m and has around £10,000 worth of furniture in it provided by the landlord: if during the lifespan of the furniture the convenience of the apartment being furnished reduces tenancy voids by a total of 3 months then the furniture pays for itself.

I don't want to expose my address but you can browse "London" on the UK property website Rightmove and find comparable apartments (same building, same floorplan) with furnished/unfurnished prices that are no different.