Selling a leasehold flat with high service charges — impossible?

Trying to sell my 2-bed leasehold flat. It's a nice property in a good area but the service charges are £3,200/year and ground rent is £350. Every viewer asks about the charges and then you can see the interest drain from their faces.

The charges cover building insurance, maintenance of communal areas, a concierge, and a sinking fund. They're not unreasonable for what you get but the headline number scares people off.

Buyers' mortgage lenders are also flagging the charges in affordability calculations, reducing what they can borrow.

How do I sell this thing without taking a massive loss?