Sorry to hear about your grandad, Tommy. Good on you for keeping the birds going.
First thing - don’t put too much pressure on yourself. YB season is unpredictable even for experienced flyers. Losses happen, birds get lost, it’s part of the game.
For prep:
Make sure they’re trapping well (coming in fast when you call them)
Start with short tosses - 5 miles, then 10, then 20
Don’t overtrain - 3-4 tosses per week max
Get them vaccinated for PMV if not already done
Which club are you with? I know a few Manchester lads.
One thing I’d add - don’t basket birds that aren’t ready. If they’re not trapping confidently or seem stressed, hold them back. Better to miss a race than lose a bird.
YB sickness is also common this time of year. Watch for any respiratory signs or birds going light. Catch it early.