Mills & Hersey London 1970's Goblets

Hi Everyone,

I’ve inherited three silver goblets through family, and I’m looking to sell. The hallmarks confirmed they are from Mills and Hersey (now Hersey & Sons I believe), from 1973, 1977 and 1978.
They are all Sterling 9.25 Silver, solid not plated. They are in very good condition as you can see from the attached photograph. Individual weights below;
129g 1978
211g 1977
150g 1973

I have been quoted a value of £980 for the set based on weight and style from a gold and jewellery merchant, but they pointed out at auction the larger one could be worth a little more as it is stamped with the 1977 silver jubilee queens head.

Can someone who knows a bit more give me an idea of how much I could ask for with these please?