Apparently there are some delivery issues with the spare batteries. It is quite strange that why.
Maybe there are some faulty batteries in the wild and that is why some people have bad battery drain?
Anyways ordered mine from Mobilefun and got this email two days ago:
"I am writing to apologise for the delay in completing the order you placed online with mobilefun.co.uk recently.
Order ID: 2229884
The following item 29442, Samsung Standard Battery - EB-F1A2GBUCSTD - is delayed with our suppliers and we have been provided with an updated time of arrival to our warehouse of Tuesday 28th June 2011. I will ensure that the team keep you updated with our progress and on receipt of the item by our warehouse team; we will prioritise onward dispatch to you.
However I also understand that any delay may be unacceptable and inconvenient for you. Therefore should you wish to revisit the mobilefun.co.uk website and choose an alternative item that is available in stock for immediate dispatch, then please reply to this email and include the product reference for your preferred item (This number can be found on the product description page of the website to the right of the image, under the product title). Your request will be processed as a priority.
Alternatively you can talk to the Customer Relations Team by calling 0844 249 5060 and selecting option 1. Our team will help to select an alternative in-stock item for you.
Thank you for your patience so far and please accept my apologies for the inconvenience that has been caused by this delay.
Operations Manager - Customer Relations