Hey
So Biological Sciences is located on the Gibbet Hill campus which is a short walk away from central campus but it's not too far, there are no halls there.
The main library is located in the center of campus, however there is the BioMed grid which is by Biological Sciences.
Bluebell is the nearest en suite, but as you've already said it is very pricey. The next nearest en suite are Jack Martin and Arthur Vick, these do have up to 14 to a kitchen, however I'm currently in Arthur Vick and it's honestly not an issue, there's never more than 8 people in our kitchen at any time and there's plenty of cupboard space, fridge space and cookers etc. Arthur Vick and Jack Martin also have the advantage/disadvantage that you have to move out over Easter, though this makes the yearly rent substantially less.
When you apply for accommodation, they will ask you questions like when you go to bed and how loud/quiet you are, the more honest you are for these the better as they try to put you with people they think you will get along with.
Finally, just a note that you have to put 6 preferences for accommodation and only 3 of these can be en suite, en suites are always oversubscribed but shared bathrooms are not too bad and they are cleaned Mon-Fri so usually they tend to be a good standard of cleanliness.