After a lot of finger clicking...The only heat sensitive paper I can find is in the USA...too far, too costly, too long. So, now looking for thermochromic inks/pigments that you apply to paper or card. 

The paint is heat sensitive, and you can mix with acrylic to make new colours.  

So I will have to book some time in with Claire Heathcoate in textiles dept for introduction and experiments. 

In the meantime, will look at story boarding what I want to happen, make a shopping list and do a flow diagram for tomorrow morning. 

If I need a specific temperature change then i will have to purchase specific thermochromic pigments. 

Books search Smart Materials in Architecture, Interior Architecture and Design: Types, Products, Architecture by Axel Ritter would provide a starting point  about  science and application of thermochromic products.

more about thermochromic dyes and pigments.

<http://www.chromazone.co.uk/?gclid=CLLlkqD67a0CFUcTfAodVxF7TQ>

<http://www.mindsetsonline.co.uk/images/SMARTCOLO.PDF>

<http://www.colour-therm.co.uk/index.html>