I emailed them with my new address details and requested a new card as I didn't get one when I renewed and this makes it difficult to get discounts.
Also cheekily asked for some mudguard stickers to put on my fixed wheel to confuse the hipsters in this fair city and....
Got a very nice email back promising all would be in the post ASAP - it is nice to know there are people at the end of the line looking after our interests