uausmani, your buyer should be charging his customer, who you are delivering to, VAT and declaring it in his quarterly return, but you should not be involved in any way in UK VAT transactions or accounting.
gadgetsquick, if you're selling retail, you would usually display an inclusive price, but you could show it nett and show the VAT amount separately. Whatever you do, you must publish your VAT Registered Number on your site, state that VAT is due on all transactions and whether or not it is included in the prices shown. Have a browse round a few sites of well known retailers and you'll see they vary how they do it, but they still follow the rules. If your business is not VAT registered, you must not charge VAT. If you are, you will keep your VAT accounts but the ones you submit for personal or corporation tax purposes will not include the VAT amounts.
Jeremy, Excise is the old name for the government department responsible for collecting excise duties. The department's responsibilities have been altered and absorbed into other departments over time. Excise duties, in the main, are indirect taxes imposed upon consumers, such as import duties.
Dioes that make anything any clearer?
Mike