You don't need a licence to operate a radio transmitter in the UK so long as it complies (or you operate it in compliance with) with the the UK's Licence Exempt rules, which for most people will generally mean they'll be using a PMR446 (Private Mobile Radio), aka a little 'walkie-talkie'. The rules in relation to those essentially boil down to: Maximum ERP (Effective Radiated Power) of the equipment is no more than 10mW (which limits its range to a few hundred meters in built up areas and a few miles out in the open) Frequency range: 446.1 to 446.2 MHz, which gives you 8 channels on analogue equipment and 16 channels on digital equipment. They are useful not only for your own comms in skirmishing, but also for monitoring 'the enemy' who are likely to be using PMR446s as well.
If you want more range (and privacy from those at a skirmish), you could use a 27Mhz 'CB radio', which (since 2006) no longer requires a WT licence (the licences were actually only 25 quid from the Post Office, but hardly anyone ever bothered to get one, so they dropped the requirement for you to have one lol). CB radios will give you more range, because they are allowed up to 4 Watts of power, and they'll also give you up to 40 channels, depending on the make and model, but the increased range may mean you'll have other people busting in on your channel doing all that 'Convoy-style, Breaker One-nine for a copy, this is the Rubber Duck in an 18-wheeler pulling in at Watford Gap services for a nosebag.' nonsense. Also note that the CB radio channels are under the regulation of the MOD, who can without notice jam those frequencies, and unlike with aviation band frequencies, where they issue a NOTAM telling pilots that they'll be jamming certain frequencies in certain areas, with CBs, the MOD can jam them with no notification at all to users, although to be fair, this does not happen that often, if ever really. Nevertheless, you can find compact mobile handheld CB radios second hand on fleabay for 20 quid upwards (and it's likely to be better build quality than a PMR446 radio for the same price, although probably a bit bigger). Since less people use CBs at skirmishes, it's unlikely that the other side will be eavesdropping on you, although as noted, the MOD might be interested in you mentioning over the airwaves that you're 'commencing a pincer movement on the machine gun emplacement' or whatever, and you'll lose the ability to communicate with most players who are using PMR446 equipment.
I've got 2 of the baofeng 888s with throat mic setup
