well, to enjoy Barcelona you will need more than 3 nights mate , my latest Uk trip was of 11 days and really i wanted to stay more time ... so 6 or 7 days would be enough...you have to think the first and last days are to travel, probably not time to ride.
You will have to add in the flight price the bag with the bike...in Ryaniar that was about 100 euros i think xD, also don't believe the first price company's give you, that's a lie. The first price Ryanair gave me to go to Leeds was about 40 euros or something, after all the process that was about 260 euros(i don't remember exactly)... so i recommend you to do all the process but without pay it to know the final price...
I live very near of the BikePark Sabadell, not far of Barcelona city, so for sure i will be available to ride with you if i'm not in the UK
let me know if you need some map of somewhere, i will do it for you as you did the Hull map for me
love you
then i think we rode together!