There are some updates!
I contacted a local airsoft club which will be closed to the town I station. They give me some information about UKARA.
1. If you want to become a member of UKARA, you need to go to their site (Registered UKARA site) for 3 times in no less than 2 months. They will help to sign the gameday off. Once you get 3 game days, give 2 photo and show passport or driving license. The will help to process your membership.
2. Without UKARA membership, you can't buy airsoft gun in the UK ... But, you can have it without UKARA membership.
3. You can import your guns to the UK without UKARA.
This is the summary from the communication between a local UKARA registered site.
OK .. For Point 2 and 3, my understanding is quite different from what we know. So, to be safe .. better to get your membership first ... Then, ship your airsoft guns to the UK with your UKARA membership number.
OK .. This is what information I collected in these days. Hope you may find it useful.