>> ...they ask about stock in hand. Do I include stock at cost or sale price?
Stock at cost.
>> Do we just close first partnership down and sell stock to other one? At what cost? cost or sale price?
I'm not sure about the process for closing a partnership down. You'll need to call HMRC anyway so ask them when you do. Also take a look at this: http://www.hmrc.gov.uk/dealingwith/c...l-business.htm
In terms of moving the stock, selling at cost seems the fairest thing to do. This would empty the inventory of the website business without brining in additional profit. If you transferred the stock at retail price the website business would look artificially profitable and the sports club would need to sell at above going rate to make a profit. On paper you'd have closed a profitable business and encumbered a new one.