Thanks for your comments everyone and sorry I have been so long in coming back to reply!
The Pringles tube - I use a hot glue gun to stick the string on. When I start winding the string round, I put glue all the way round under the first three or four wraps - then I just put a little blob here and there, every three or four wraps - it would take so much glue otherwise! I make sure I wind it really tight. Then when I get to the end of the tube, I put glue under the last three or four wraps. Of course, if your hamster decided to chew from the middle, this wouldn't be so good!
Hope I have explained that well enough - I was thinking of making another tube and taking some pics but I haven't got much string left - so annoyed because it's a good thickness but I can't remember where I bought it! I think I remember getting it from Hobbycraft but I couldn't see any in there the other day, but they were moving all the stock around.
Serendipity I use a DSLR, just and entry level Nikon but with a separate flash gun so I can bounce the flash off the ceiling, I think it's the flash that makes all the difference and it doesn't seem to bother Marty!
Well - Marty moved into her house Christmas Eve - I cleaned her nest out the day before and it was so disgusting, she had peed on her bedding and shoved it all up the back of her box. Bleugh!
So I started moving her belongings over during the afternoon, and when she got up (after a good 20 minutes!) to see what I was doing, I popped her in the new cage.
Here is how it is looking at the moment - a bit more lived-in! There are still things I want to do but I will take it slowly.
Oh my goodness there is too much of my messy bedroom showing in the background! Blame it on Christmas!
Marty spend about 20 minutes parading round, gathering up the pile of food from her hoard that I put in the new cage, then decided to go and make herself comfortable in her Rodipet house.
And - er - I have hardly seen her since.
She has decided I am NOT her friend any more and I am NOT to be trusted.
Hoping she will get over it - I suspect she is reasonably happy in her new home, as I have heard her out playing at night, she gathers up all the food I hide around the cage for her, and there has been no bar chewing whatsoever.