It's an amendment application to the original outline planning approval.
http://www.n-somerset.gov.uk/NR/rdon...registered.pdf
http://wam.n-somerset.gov.uk/MULTIWA...df&pageCount=4
The second link (applicant's letter) is interesting as it explains the reasons for the various proposed alterations.
Addendum
I note that three of the nearest parish councils have written to the local authority saying they have no objection to the proposed amendment.