Thank you for your advice guys!
I found out the cage was slightly too small after I bought it- but thought I could just extend it a little later.
I had a look at your suggestions and I really do like the Barney cage as there's a lot of space for toys, whereas the Alexander looks quite rammed with all the wooden bits.
I don't think I'll be able to take the Pets at Home one back, as there are marks on the bars from opening the doors etc, but I'll just have to wait a little while to invest, I think. Just out of interest, would there be any plausible way to connect the two? Since I already have mine and probably won't get a lot back for it.
Thanks
