Hmmmm......I'd have to be pessimistic & say gearbox I'm afraid!!!

Sounds like its something to do with the primary shaft although I might be wrong!!!

Just as a matter of interest - does your speedo still work when you apply drive but you obviously dont go anywhere??

Usually when a clutch fails completely unless its completely lacking friction material which will obviously make it slip you usually find it hard to get gears first!!

But yes a gearbox/clutch change I should imagine you can tackle on your own - obviously ramps would be a significant advantage either way!!