My adopted home town has a tea room probably every other shop!!
I've been making/preparing/serving afternoon teas for over 30 years either professionally or during leisure time.
Personally I don't think sausage rolls are appropriate but it's personal choice.
If you want to stay as traditional as possible:
I would serve for savoury:
Classic cucumber sandwiches, watercress, smoked salmon and cream cheese, good roast ham and mustard, roast beef with a little horseradish sauce, egg salad - sliced not chopped egg and only a little good quality Mayo, cheese and tomato chutney.
You can choose either small triangle shaping or finger sandwiches but certainly cucumber are traditionally served as crust less triangles.
Less traditional but in keeping I think:
Small quiche, tartlets could also be served.
For sweet:
Scones (of course) not usually fruited. Served with clotted or hand whipped cream and strawberry jam.
Victoria sponge - strictly speaking should be raspberry jam as the sponge is sweeter than a scone and the tang of raspberry balances.
Fruited tea loaf
Patisserie - Millefeuille, mini eclair or choux buns
Biscuits - shortbread, langue de chat, Florentines
Choice of teas is good, again strictly traditionally you'd serve Indian teas in the afternoon. It may surprise people to learn that earl gray is actually a morning tea (traditionally).
Whether you go traditional or more modern hope you have a lovely time.