You are right.

Throughout this period, Britain had the most powerful and probably the 'best' navy in the world.

Britain was also the richest country in the world through most of this period, which certainly helped.

Through most of this period, Britain, being blessed by being an island nation, with no land borders to defend, did not have a particularly strong army.

There were only two times in the period when Britain's army could be possibly described as world class.

One was in the latter stages of the Napoleonic wars, when the British army that fought its way across Spain into France, and contributed strongly to the victory at Waterloo, was very good (though still not very large compared to some of the other armies of the time).

The second was in the latter stages of WWI, when Britain had a very large army which was perhaps the best in the world.