Thanks Dan42, I appreciate your prompt response and information provided within. Question 5 was probably a little confusing. To make it a little clearer, it should read;

If I was to build an extension onto the existing house, can the business pay for this as an office extension/refurbishment as long as the business operates from the new extension? Apart from the CGT you have already outlined, would there be any further tax implications if the company did pay for the extension?

Thanks again for your responses.