Congrats on the lottery draw! My husband tries every year, and has been selected twice, run it once.* This will be your first marathon?
Personally, I'm with KF; I only run from danger -- and even then I have to be really convinced.
*My husband successfully completed the 2012 London Marathon. The second time he was given a place was the year we bought our house (2016, to run in the 2017 marathon), and with moving and the commuting situation, and adjusting to our new reality, he didn't have time to train. He paid the fee to secure his place with the intention of deferring to this year, but then he forgot to log in to defer by the deadline (he remembered at about 10pm on the "by close of business day" deadline), so he forfeited his place and his fee. He was really disappointed.