amt ertl / airfix star destroyer

[the clone]

after reading on many forums (including this one) about the 1/4222 scale star destroyer being able to be picked up for a couple of quid i was surprised to find on eBay and amazon it going for in many cases over one hundred pounds. i am not interested in it having lighting or fiber optics so that isn't an issue, i was wondering if anyone knew where to get one preferably under £25 in the UK. Have i missed anything? am i looking in the wrong place? please help me out
the clone

 

[the clone]

something else i thought it was worth mentioning is that i am looking to use it as a donner kit for a 'harrower class star destroyer' and so would also appreciate any links to place to get parts of the model not just the complete model, thanks

the clone