What wasn't allowed in a pub in 1914?

Quite a lot of things, as it turns out. Some of them pretty understandable.

The first set mostly refer to pissed-up punters.

2.—As to Public Order.
Offences.-Any licence holder is guilty of an offence against the Licensing Acts and renders himself liable to a penalty not exceeding on a first conviction £10, and on a second or any subsequent conviction £20, who by himself or by his servants acting within the general scope of their employment does any of the following things:—

(1) Selling to Drunken Person.—Sells any intoxicating liquor to any drunken person. Note.—If the person to whom the liquor is sold is in fact drunken the offence is committed whether the person by whom the liquor was sold knew him to be drunken or not.
Brewers' Almanack 1915, page 305.

To put those fines into context, a pint of Mild cost 2d. Ten quid, then, was the equivalent 240 pints of Mild. Quite a sum.

More about drunks.

(2) Selling to Habitual Drunkard.-Knowingly sells or supplies any intoxicating liquor to or for the consumption of any person, notice of whose conviction has been sent to the police authority under Section 6 of the Act of 1902 within three years of the date of such conviction.

(3) Permitting Drunkenness.-Permits drunkenness to take place on his licensed premises. Note.—Where a licensed person is charged with this offence, and it is proved that any person was drunk on his premises, the presumption will at once be raised that the fact of the drunkenness was known or connived at by the licensed person or by the person left by him in charge of the premises, and that presumption cannot be rebutted unless the licensed person proves that he and the persons employed by him took all reasonable steps for preventing drunkenness on the premises.

If the drunkenness is on the part of a lodger on the licensed premises, or of a private friend of the licence holder, the licence holder will still be liable to conviction; and it is immaterial whether the drunkenness takes place before or after closing time.

(4) Permitting Disorder.—Permits any violent, quarrelsome, or riotous conduct to take place on his licensed premises.
Brewers' Almanack 1915, page 306.

You get the idea. The authorities really didn't like the plebs getting pissed up and causing trouble. Those killjoy bastards.