Don't feel bad about Chloe having accidents. They happen at all stages of their lives, believe me. My 2nd DD would climb anything at any height. After the first few times you stop feeling guilty, pick them up, dust them off, give them a quick once over to make sure they are O.K and wait for the next time. As for the clinic nurse just remember that many feel their way is the only way, also it is just a SIDS recommendation. Its sad that she is not flexible as any mum loves a few words of encouragement especially when its your first. Just remember every child is different, thank goodness, so what works for some mums/children won't work for others.
All the best with your beautiful DD