I should really ask what its condition is like first but I'm assuming it'll be pristine since it has been in your possession. About £25 or £30 to me - willing to up it if the offer is not up to scratch. Aye, vinyls are expensive to post.
Last time I saw them on eBay they were £20 max. Not a coveted item of mine either though it is nice. Would take somewhere around £10-£15 plus shipping.