Congrats!
I attended last year (disclosure - as a speaker so I didn't pay) and I felt it was a professionally organised event with lots of interesting delegates to network with. I know I didn't pay but I thought it was good value - lots of good speakers (don't mean me!), networking and the goody bag was so heavy I could barely lift it - including Martha Stewart stationery .
I am not naturally a fan of the 'Mumpreneur' label, but the event focused on being business women more than mums with businesses.
They invited a few previous winners back to speak including Nosy Crow Publishers nosycrow.com/ the owner did an amazing speech about her business journey.
If you are "into" inspirational speakers/events then it is worth going just for that. The other delegates were also very inspiring, I met all sorts of women.
I know they do give out various accolades (the 100 list etc) but I get the impression that the awards are the highlight of their year.
I sat next to the owner of this spa at lunch www.thepottingshedspa.co.uk/about-us/ and she won last year and mentions in on her site.
I assume the finalist list is fairly short, so you have done well to get on there.
No idea if not attending will effect your chances of winning, one would hope not, but you never know...
However I would have thought it is worth £59 (and any travel) to go and make the most of being a finalist and to enjoy the event...
Having said all of this, the true value of awards is what you spin out of them before and after, so make sure you have your finalist status everywhere. Sorry if you know this/have already done it.
Not sure if that helps!