I know im late to the party here but let me give my two cents for ordering RIFs and other things from them.
When you order anything from Ehobbyasia be it parts, clothes or a RIF then i think its in step 5 or 6 that you have to request that they put the UKARA no on the box, they even mention during the checking out process in small print that if you live in the UK they need your UKARA no.
Once paid they will process your order and ship it, it you have asked for express shipping they will normally dispatch in 1 or 2 days, if you have asked for non express then they ship every Friday. RIFs or particularly high value orders will only give you the option to ship it via express. Their shipping is normally handled by HK Post: http://www.hongkongpost.hk/en/home/index.html and they always provide a tracking no.
When the item arrives in the UK one of two things will happen.
Irrespective if its normal or express shipping it will pass through customs.
If the stated value of the goods is higher than about £80 (i think but dont quote me on this) then the package is immediately handed to Royal Mail who will treat and deliver it as a normal parcel.
If the value of the goods is much higher (such as an APS CAM870 Salient Shotgun like i got) then the item first goes to Coventry where its assessed by HMRC, customs charges are raised, then revised before being released and handed over to Parcel Force. Parcel Force will then have it sent to the National Hub to be sorted and sent to your nearest depot. Once it arrives to your nearest depot a letter will be sent to your home address asking you to pay the charges, once the charges are paid they will deliver. Alternatively you can attend the depot in person, show ID, pay the charges and get the parcel released to you.
Ehobbyasia are not a dodgy HK company, they will state the exact price you paid for your goods and will declare it as sporting goods, if UKARA is required they will affix a large A4 sized sheet with your UKARA no clearly displayed in a clear plastic envelope.
HMRC VAT, Duty and Parcel Forces Handling charges will vary based on what you have bought and for how much, Parcel Force has a flat £8 whilst VAT is charged at 20% and Airsoft goods i think the Duty is 12.5%, these percentages are calculated on the value of the goods including cost of shipping.
In my example i bought an APS CAM 870 Salient Arms shotgun originally worth $500, got 30% ($150) off so the final value of the gun was $350, cost of shipping was $91 for a total of $441, the shotgun was shipped and i was charged £107 for HMRC VAT, Duty and Parcel Force Handling fees. It took exactly a week from shipping from Ehobby Asia to me collecting it, bare in mind it can be slower but a week is about average.