Hello Margaret:
Value:
The current rights to the Clarkson's range of castings and drawings is held by Blackgates Engineering. I don't know how much they are quoting for the castings & drawings, but an enquiry may elicit some information.
The same locomotive, drawn and prepared by a different designer is available from Reeves 2000 as Roedean. You can see that the full set of castings with drawings is approx. £1250.
As to how-much your castings are worth I'm afraid that it is whatever someone is prepared to pay. Generally castings sold-on like this sell at a heavy discount to the original price. Model Engineers love a bargain!
You should also note that Clarkson drawings are generally not highly detailed and, whilst I am not familiar with particular Clarkson design, often need skill in interpreting and making the parts. An ongoing series in the magazine 'Engineering in Miniature' which involves the Schools Class V may stimulate some interest in your castings.
How to sell:
Ebay will let the market decide a value for you, and you can of course have a 'hidden reserve' if you wish. Naturally there are fees involved reducing your return, however you do not have to decide the value.
Otherwise/in addition you can advertise here or on Model Engineering Clearing House. I would always recommend stating a price in adverts placed in website small-ads if you can, rather than asking for 'offers'. In addition, no matter how you sell, I would strongly recommend offering delivery – you simply pass the cost on to the purchaser, but it widens your market so much.
You always have the option of selling to a dealer. They will give you a quote by email. You will receive an absolutely rock-bottom price but it is quick and easy from your point of view simply requiring you to send the castings etc. to them. Station Road Steam is well known, but there are others which a search will find.
I have also sent you a Personal Message. You can access this by looking on the thin green banner near the top of the page and clicking on the second icon from the left. If you have a message it should be 'flashing'.
Regards
Phil