Apologies if I was not clear. That is the answer the lady in the call centre gave me.
I have had a contract with Virgin(NTL) since 2003 and it doesn't have an expiry date and I have not had new contracts after previous upgrades which Virgin has initiated.
Lady was unable to explain why my contract had expired, other than continually going round the loop of saying it was an offer for the 100MB.
Good news is; I rang on a different number to a different department who could offer no explanation as to why I had received the new contract and have told me to ignore it and the account is noted up accordingly.
I didn't apply for anything as far as I am aware. I got an email sometime ago saying the upgrade was being rolled out in our area and they would let us know when it was complete. This has been a similar approach to all previous upgrades since I first had the NTL service with a 600k connection. Both contact centre people I spoke to confirmed something happened around the 17th April. But neither could tell me why nor confirm if I had asked for it.