would spend that money of course and leave 10K for poker
Bank 50% then add 40% to my poker bank role and 10% to my pension pot. Play tourneys with max buy in no more than 0.005% of poker bank role (max £200 buy in). Extended to 0.03% max (£1500) once every 3 months. Any win under £10,000, 80% back into poker bankroll, 20% added to pension pot, any win over £10k same principle. Until the bankroll is exhausted at which point I'd retire. 50k is at least 250 games with decent prize pool. Not to mention the number of satellites you could play to save money on entry fees for big games.
If you can manage to reach top 20% of the field 50% of the time and reach the final table 5% of the time for 20 years you'd have a decent pension (minimum £500k)
It's a big ask, most people that try will last less than 18 months, 20% less than 3 years, 5% make it to 5 years 3% 10 years and 1% 15 years and less than 1% make the 20 years plus!
99.9% of all players don't start the journey!
The Journey being £40k bankroll spending an average of £750 per week on tourneys (including food and travel).
You can't really start unless you do win £100k, which was your question!