The Borrins Moor trip is billed as a family caving day, so there will be children on the trip too, who probably won't have wet suits. The usual Borrins Moor trip is in through the big entrance, maybe along the dry dead-end walking passage to the right (which has photo opportunities), then back along the main passage to where the ceiling drops. Then it's a hands and knees crawl in water relieved by a gravel bank from where you can begin to see daylight. Many of us have done it as one of our first trips, clad in only old clothes (avoid cotton) and old waterproofs. You will have a great day.
If you turn right in the middle of the water, there's a maze of crawling passages of different characters leading to three other entrances. It's a more interesting cave than many people realise.
Don't worry about the BPC application process - it's designed to weed out nutcases rather than to select the elite. They're a welcoming bunch.