Revival first-timer - dress code?

[OzzyR1]

Been invited as a guest to GW revival on the Friday.

Think we will be in the "mess" area and from reading around period dress is encouraged.

I don't own anything that would remotely fit that bill and would prefer not to buy vintage stuff that would likely only be worn for one day.

Would a suit jacket (not solid blue/black), smart dark jeans / chinos plus a decent pair of shoes be OK?

Thanks

[OzzyR1]

Cheers both, hadn't considered a hat/cap so will look at that.