Not of interest Simon, as I have something similar already (Gamo PT85 / Weihrauch HW40).

Not familar with your Walther, but a look online suggests they currently retail at over £150 gun only, so worth making the effort to find it a new home.

Do you not have any airgun clubs in your area ? At least one of my local clubs has a board where you can put up a "for sale" advert. I would expect RFDs to offer a derisory amount to buy in (Ooh, no demand for those - too much risk for us to sell second hand - look, as a special favour to help you out, if you give us £20 we will take it off your hands ...) . Some RFDs sell on commission, though.

Gunstar has a bit of a bad reputation & the Airgun Forum small ads is closed to members + you have to make 50 posts to gain access after the scheme meant to help out members was abused. Gun Mart has a small ads section as does Airgun World magazine - don't know if free or paid, though.

All methods of adverising do require posting contact details & I can understand why you would not want to do that (I wouldn't !).

Nigel B.