It is a good idea, but the charges a high.
The Duty charges they charge for the 'free' membership is: 27.5% of the parcels value.
Then add the shipping costs which for the 'free' membership is as follows:
1 kg  £39.10  
2 kg  £44.20 
3 kg  £50.30  
4 kg  £54.40 
5 kg  £58.50  
6 kg  £65.60  
7 kg  £69.70  
8 kg  £73.80  
9 kg  £77.90  
10 kg  £82.00  
11 kg  £86.10   
12 kg  £91.20  
13 kg  £96.30  
14 kg  £101.40  
15 kg  £106.50