What British control of the Baltic could change in 1915

What if Britain gained a Malta-like base and naval control off Germany during the First World War?

Germany would face blockade, stronger Russian resupply, and a costly coastal-defence dilemma because the threat of landings would force troops away from other fronts.

In this Heligoland Bight counterfactual, the strategic value of a British 'Malta' off Germany would extend well beyond launching an invasion. British control could cut German imports through the Baltic while supporting the resupply of Russia. Even the threat of amphibious landings would force Germany to defend several possible points along its coast. Thin garrisons could be overwhelmed, while stronger coastal forces would have to be withdrawn from the main fronts. Sea control would therefore create economic pressure, reinforce an ally, and impose a troop-allocation dilemma without requiring Britain to land immediately.