it's difficult to really find something super relevant for the UK so if my suggestions seem "weird" cut me some slack.
Try reading METARs and TAFs and seeing if you can "go". What are your options wx wise? Turbulence? Risk of windshear? Xw?
Do you have restrictions on your xw limit if the runway is wet or contaminated? (should be yes)
Passenger brief. Learn how to give it without using alarming language. Turbulence will frighten the crap out of nervous flyers, "bumps" is much better.
Take a mate with you, brief him/her to "announce" a diversion to X (obviously somewhere that you can land at) at a time when he/she feels. You plan and do the divert. That'll get your nav skills up - but more importantly, your confidence to handle surprises. Best do them paper flying first. Just so you know what the priority is. "Aviate, navigate, communicate". Main things to consider in no particular order. Fuel? Do I have enough. Direction? What airspace am I going to fly though? Time? When? Can I land there? (that's a tough one - ask ATC - paper exercise)
Now, how much relevance is that to "modern jet airliner" style flying? Directly. Stuff all. But indirectly. A lot. It'll teach you to think, be proactive, plan and be safe.
You could do a tonne of "practice pans" but (now I'll be shot down in flames) all you'll do is annoy every one having to monitor 121.5 on Com2.