Have tried it both ways and found neither very satisfactory, tho I have never used a 'sell it yourself' agency
There are several of these companies offering DIY house sale packages. Google it and you'll see them. They all charge (variable amounts) and it depends how much you stand to save by avoiding EA fees and also on how quick you need to sell.
You will not really be able to achieve the same type of advertising profile doing it yourself, but maybe you don't need that if your place is in a 'demand' area?
One big marketing thing that the DIY sale people say is that 'no one can show your house like you can', but when I did viewings, I found it was actually a disadvantage.
I found it very difficult to be disconnected and got some feedback that people felt that I was showing them around my house rather than presenting to them what could potentially be their house.
If you could get a friend to do the viewings, maybe it would work.