Your answer was not there when I started typing.
Right, that is the reason that they are asking, because your £1 share is capital which you own. Your balance/profit and loss account should give a rough value of each share (based on the capital value of the company). You are not being asked to disclose this as company director, but as the sole shareholder.
YOU own the company - you could have 400 directors but as the only shareholder, the Directors should act on your behalf. If the company accounts are in proper form, it should not disclose any of your contracts (if they are not in proper form, that is for your accountants to fix). In any event, you can redact anything that is subject to potential confidentiality (and this does not fall under the companies act, this falls on contracts between you).
Because you are the sole shareholder and one of the directors, the Council are taking the view that they can "lift the corporate veil". And in cases like this, they are entitled to ask - not because of your position as a director but as the shareholder in a private limited company with unquoted shares.