UK Stocks-Factors to watch on April 4

April 4 (Reuters) - Britain's FTSE 100 index is seen opening 15.8 points higher on Tuesday, according to financial bookmakers. * SHELL: Royal Dutch Shell's integrated gas and new energies director, Maarten Wetselaar, said on Tuesday that destination clauses in long-term liquefied natural gas (LNG) supply contracts that have linked suppliers and customers for decades are "not really crucial". * BP: BP Plc has agreed to cut about 5 million pounds ($6.24 million) from Chief Executi