You are not breaking any rules - you can even advertise it in the For Sale pages free. If you do I would suggest you include the location clearly in the post to help google bring you people and also to stop the many UK people wasting your time!
Pricing for RIBS and SIBS depends on many things, like the demand for the boat in the local market which nobody here will be able to advise on. It strikes me as being a bit "industrial" for the typical southern Europe market? No seat may put people off a bit? But Trailer, Engine, Boat, Console for £1350 GBP doesn't sound a bad deal to me. It is quite old though. If it was in the UK and in a rush to sell I'd stick it on Ebay, you'll know better if people sell boats that way in your part of the world. If you want to maximise value - you will probably get the most by splitting it into engine, boat and trailer.