Ed, I am going to have to disagree with you again.
It is far easier to buy RIF's than air guns. You can buy a RIF with no record being taken (most shops will record UKARA, or whatever evidence you use to provide them with a defence, for their own defence, but there is no compunction in law so to do). When an RFD sells you an air rifle they have to record name, address etc. in their ledger. You don't need to be a registered firearms dealer to sell airsoft guns as trade (private sales are different) and there is no need for RIF sales to be face to face.
Also remember (yes, this argument again) you CANNOT commit an offence by purchasing an RIF. Whether you can prove one of the defences or not (except if you are under age of course, different argument then). It is not an offence to own or buy one.
The OP could quite legally BUY a RIF, but the person selling it to him would be on dodgy ground if asked to prove their defence under the VCRA.
Buying abroad and bringing back in hand luggage is monumentally stupid. Firstly, if you IMPORT (in your hold luggage still classifies as importing) without a defence then you DO commit an offence, and could face stiff fines. Secondly, if you try to smuggle it through without declaring it then you are likely to end up with a couple of very real MP5's pointed at you. I'm not saying you will get shot, the coppers are generally pretty well disciplined, but nerves can make trigger fingers veeeeery twitchy.
So yeah, if you want a RIF, then you need to prove to your seller that you are a regular player. Why not see if you can set up a group on the islands? There must be a few blokes you can cajole into running round getting shot at, though having shot up there a few times with bigger stuff, good luck hitting anything with that wind!
Air rifles are good for target practice. Far more accurate than airsoft guns, and actually pretty useful for pest control. Shoot a rat with an airsoft gun and all that will happen is you'll hear him laughing as he runs away. Shoot him with an air rifle and he's not going to be laughing, or running! Be aware though that the Scottish Parliament are trying to wrest control of firearms low from London, and if they succeed it looks likely that air rifles will be made FAC only toys!
Jae, I'd be careful suggesting things like that. For it to count as an IF, it must be 51% one solid, bright colour as laid down in the rules. Covering it with camo tape would be the same as painting over it or colouring it in with a black marker pen, and would be MANUFACTURING AN RIF. Do that without a defence and you are open to prosecution, bit different to just buying one!
Tariq, having gone through the process of getting FAC and Shotgun certificates, it's not as simple as you suggest, and there's the fact that all shotguns are registered to you and therefore traceable.
The whole VCRA thing is to try and stop the type of oik who goes along to an airsoft retailer, buys an RIF and then flourishes it to try and scare people. They're unlikely to spend the £100 or so for an air pistol to do that. Putting the onus on the retailer takes the responsibility out of the hands of the irresponsible ones who have nothing to lose, and means that if the shopkeeper flouts the law they stand to lose everything. It's a pretty good incentive I'm sure you'll agree!