Evening trousers on a budget

[dementedma]

Help! Have VIP evening event soon which will run late into the night and be outdoors. Black tie for men but evening trousers rather than long dresses are acceptable for women, given the venue(castle) and climate (Scotland).
What can I wear which will be warmish ( first part of the evening indoors), but formal and not expensive.
Am 52, size 14 to 16. Can't wear killer heels as ground is cobbled.

Have a look here www.justlastseason.co.uk/trousers-1/

They have some nice satin piped evening trousers and some lovely formal wide leg ones. Bargains too

Ooh thank you