Just wanted to add that sending a single letter recorded delivery and tracked will only cost a few pounds and is well worth it. Proof of postage is not proof of delivery at their office. Things do get lost both in post and at their post room. I sent some important docs next day delivery so I cd track them and had a signature to prove delivery. I rang up 2 days later to make sure the doc had been handed to my case manager...it hadnt. I insisted politely that they search for it. A few hours later it turned up and was given to the correct person.