Thank you for the thoughtful reply Kev.
(It's my husband not my dad)
He has just had the biopsy and they only took 4 cores to grade the cancer.
I'm assuming this is because the MRI showed cancer all over the prostate so there was no point doing any more :-(
I was going to ask if anyone else has had only a 4 core biopsy but I feel that I am increasingly clutching at straws.