I run a small online e-commerce site for items I manufacture myself. Can I offset the cost of the online site & store against my tax? I upgrade & redesign it every year to 18mths to keep it fresh and interactive.

I am a sole trader and spent many hours myself designing, creating the site and updating it on a regular basis (security upgrades, new products, search engine optimisation etc). The site and interaction through it (and social networks) is essentially my business and advertising/marketing.

This has totalled many, many hours of work. I know if I'd have contracted someone to develop the site for me I could claim these costs as expenses but as I have built everything myself, am I able to charge a fair cost for time & development against tax.

I hadn't considered doing this but was told it could be possible?

Any advice would be greatly appreciated.

Thanks