I agree with Lapras that people who are successful in their fields would be good.I have long believed that the second house should be made of 100 citizens belonging to no political party, elected every 4/5 years by some form of proportional representation.
100 people. 15 from law backgrounds. 10 from medical. 10 from education. 10 from military / police. 5 from each of Britains key industries. All elected from within their disciplines. Good wage. Ten year role. No political allegiances allowed. Circular chamber.
Absolutely random splurge of thoughts but we don’t have to stick to the old ways.