New build help for uk fibre 80/20

[kylepiggy]

hi guys need some help building a pfsense router i currently have plusnet fibre 80/20 internet which could possibly be 150mb within the next year so would like to build something futureprooof

my requirements are
fanless
power efficient
possible addons to be able to run
budget wise if i can do under £250 that would be great
allready have a 240gb ssd i know overkill but its new sitting in a box so might as well use it lol

the router will connect to a 24 port tp link gigabit smart switch. will be running around 5 computers in the house and have a dedicated 12tb server on 2012r2. Was thinking of using my existing asus rt-n66u as the wireless ap. any help would be awesome as bit confused which setup to go for would rather build it myself unless a ready made setup will meet my needs no issues there been building pc's for around 10 years but never a router. Thanks in advance