If you want to get in somewhere now is definately the time as it gives time to bond with team aswell.
Good luck with the sandhurst stuff as well, almost went there my self after being extensivly involved in various cadets stuff. Starting to regret it now as they offered to pay for me to go through uni.
To be honest if you have £250 for a marker I'd go for a PMR or a SLG mainly because I'm not a big fan of smartparts and cant fault my UL PMR. I'd go for a good hopper and pair of goggles as you don't want to be shelling out more in 6 months for an upgrade.
ignore this just realised it was started in 05