short
boots like these only nicer. More shoe boots and with a small platform. Very comfy and strangely very flattering for the legs.
long dress
sandals similar in style to these but blue/petrol not gold. Very sparkly, not so comfy.
The do is a Christmas party, officially smart casual but men will mostly wear suits and the women dresses. The long on is probably OTT, although people will dress up, but it (size 10) fits like a glove and I have another do requiring a long dress in the new year.
If I went for the short dress I'd wear opaques and the shoe boots
The long dress probably wants the sandals but I'm not sure about sparkle with sparkle and with that split my legs do need a bit of help from some lovely sheer tights, so sandals no good for that. Could I wear it with shoe boots? Might dress it down a bit?