Hmm £30 gas gun does not seem like a good idea. Honestly sounds to me like you're lookin at the fookin "BB gun" websites
It's a good idea not to buy from them. People would also say you should buy a rifle first and not a pistol, whilst true most of the time, it depends on your local site. If you're doing CQB a lot I'd say it's the other way around.
I've already gone over it a bit in your other post but basically research and make sure you know the manufacturer is reputable. Too many of us starting off ourselves have gone and bought kinda crappy guns.
For example I've got a CYMA M4, had it for a couple years, can't get any more now until I'm 18 (in November) IMO was a waste of money because I could've bought a much better G&G for £117+ and good batteries and smart charger (say £160 in all) whereas instead I paid £150 for a worse gun. Shouldn't really complain because it is okay but disappointing knowing you could have had better.
Also already have a Classic Army MP5K so should've concentrated on upgrading that. I thought ooh yeah M4 can upgrade it etc turns out the thing doesn't even have a standard delta ring / barrel nut assembly nor even a threaded barrel.
TL;DR
Basically get the shotty, don't bother with the pistol until you get your defence. Then I'd say spend £100-£130 preferably on a Tokyo Marui (they last years, easily the best you can get) With your UKARA you could also consider ordering from EU retailers like Gunfire.pl or TaiwanGun (both actually Polish) and potentially save a bit.
I'm sure you know this but I like to say always shop around and check out manufacturers / retailers cos it will be very helpful and we see a lot of people will make those kind of mistakes