Perhaps the following information might be of use with regard to this web site. Apologies if I'm teaching granny to suck eggs!
The domain name for the web site is
http://www.yorkshirefurniture.cjb.net. Which means that you are locked into that ISP forever because the cjb.net part of the domain name will always be under the control of their servers. You won't be able to move to another ISP because of that, so they've got you by the short and curlies.
If you publish stationary with the URL or email address on then you won't be able to make a switch later on without seriously denting your customer loyalty base.
This current arrangement probably means that these popups are a feature of the web site whether you like it or not. I just reviewed their sign up process and they don't apparently ask for any money - and they give instant availability of the chosen domain name - so they are most likely making money out of free advertising that you are giving them whenever someone goes to your web site. That's very nice of you to offer that service isn't it?
I suggest you forget about the current hosting arrangement because it'll probably cost you customers who will rapidly get fed up with having adverts pushed in their face. Plus, how's about your web site disappears frequently as you push thru the bandwidth? Or how's about these adverts being used to distribute viruses to your customers? And maybe some of these adverts are pornographic which won't do your customer respect any good!
The alternative is to buy your own .co.uk domain name (that'll set you back about 15 quid for 2 years I think), and host it somewhere where you don't get punished with adverts etc - there will be a cost for that as well, it depends on the ISP what this cost will be. Without wishing to bang my own drum here I provide web hosting for customers because I have a reseller account with an ISP (no adverts 'cos I charge for the service!) so please contact me offline if that might be of any interest.
Even if you don't want to host thru me I'll be happy to help you get this sorted (I won't charge for that). I think you've made a good start with your web site and it would be a real shame to spoil that effort by keeping it on a 3rd rate ISP.
Andrew