The original text:
[...] For them the working hours are never long enough. Each day is a holiday, and ordinary holidays, when they come, are grudged as enforced interruptions in an absorbing vocation. Yet to both classes, the need of an alternative outlook, of a change of atmosphere, of a diversion of effort, is essential. Indeed, it may well be that those whose work is their pleasure are those who most need the means of banishing it at intervals from their minds.
What does the first "it" refer to here? I think the second "it" refer to "work."