Thank you for the suggestion, Ekimp, but I don't think the two signatures are close enough to indicate the same studio or artist.
Nor do I believe, the vase to go with the signature is Caithness: it was suggested the vase could be Caithness CT151. But if you compare the image on
http://glassgallery.yobunny.org.uk/displayimage.php?pos=-7943 with the attached image of CT151, you'll agree it's not the same vase (despite daffodils as theme in common). Whilst I might be wrong (my main topic are the paperweights, not glassware) I don't remember having seen this shape from Caithness before. Colour could be Harvest Gold - but this is very difficult to say from photographs, were the lighting has a big influence.