The decision by UK grocery chain Wm Morrison to extend its opening hours may help improve weak like-for-like (LFL) sales trends, but the future of its dividend remains uncertain, according to Shore Capital which kept a 'sell' rating on the stock on Monday.The broker said that "uncertainty and poor visibility" contribute to its cautious stance on Morrison's shares.Bovis Homes remains Panmure Gordon's top pick in the housebuilding sector after a "positive set of interim results" on Monday."Along with a positive outlook statement, the group has outlined its future strategy including a programme of enhanced dividend payments. This newsflow is likely to be taken positively in our view."Canaccord Genuity has repeated its 'buy' stance on Petra Diamonds, but has said that current-year guidance from the miner was worse than expected on Monday."This means that the company will be more reliant on the continuing strength in diamond prices, the sale of the exceptional stones (including the recently found 122-carat blue diamond) and the available debt facilities in the year."BC