It's the first link. I have noticed they have a branch in Sussex so may be worth going their after work one day & buying direct. The cost of posting it is more than the fuel i would use to get to them!
I use a company called CPC-Farnell click here who have a very large range of various goods including electrical- electronic testing equipment. The prices are okay, and even better if you can get a voucher code or promotional offer.
Delivery is usually next day, and free over a certain purchase price.
I have also used the company who wiz-king as provided a link to. Never had any problems with that company.