To be honest, they'll be lucky. I have some knowledge of the UK reserve forces, and right now there is a massive attempt to recruit as the government tries to switch its defence manning policy in a very, very short time. Unlike the US and Australia and various other modern forces (which have a much greater proportion of reserve forces), the UK has until very recently has a relatively small reserve forces. It's common in the US and other such for reserve forces to be part of the routine planning and deployment for operations; the UK has only recently been forced to think like this, principally due to the manning issues encountered in the Middle East over the last decade.

Fifteen years ago (maybe even ten years ago, depending on which reserve force one joined), you could join the UK reserve forces and the general feeling was that one could easily go a few decades without being mobilised; now, people are told on joining to expect to be mobilised - it's routine.

The US is a very warlike society, with a significant civilian buy-in to the idea of the armed forces and reserve forces. The UK, whilst as a nation just as busy travelling around the world to meet interesting people and shoot at them, does not have nearly such a civilian buy-in; there are already rumblings that reservists are just less attractive to employers on the grounds that they can be expected to disappear for nine months, and the employer is forced to hold their job open for them. This is clearly a big concern for the government, because they're trying to push the idea that employing a reservist brings advantages. Many employers seem... dubious that losing someone for nine months is worth the less tangible benefits.

Some reserve forces are being asked to increase on the order of 50% in about 5 years; given that in the UK it can take three years (and sometimes more - five years isn't unheard of; I understand that in some nations, reservists might spend several weeks or even months doing all the initial training in a single block; that simply won't work in the UK unless civilian attitude to reservists undergoes a massive change) to take a new reserve recruit and make them deployable (on the "trained strength" as the vernacular goes) this is one hell of a recruitment target.

The network infrastructure reservist branches are still in their infancy; in the British navy reserve, the branch is very, very new. They are still working out just what they're about. The kind of IT professional I anticipate they'll be trying to recruit will almost certainly feel a bit ripped off to be exercising their years of experience (for which, as contractors, they probably charge up to a hundred a day) on initial pay which, as I recall, is around 40 UKP a day, before tax etc. The initial basic training and militarisation can easily take a couple of years anyway, before they even start thinking about branching, so this might be something of a hard sell; "join us, and spend two years slogging around fields in the mud, and eventually we'll use your civilian skills at a much lower rate of pay than you get for them in your day job". Given that one of the main selling points of the reserve forces in the UK is that you get to do something a bit different, this is going to be a very hard sell.