actualy "varjak paw" has the totally wrong info according to apple website the model A1459 will only work in usa,canda,mexico... while the model A1460(verizon) will work in most of countries (usa,autralia,uk,europe,etc...)
further more apple store in the uk only sell the model A1460 ONLY ! as this's the one that would work there and in most countries u can double check that with the store they'll tell you they dont even have that A1459 model
Also A1459 is gsm that's correct but so is A1460 ,the difference is that A1460 also has the ability to work on CDMA
see below (copied from apple website) :
Wi-Fi + Cellular
- Model A1459*
- GSM/EDGE (850, 900, 1800, 1900 MHz)
- UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz)
- LTE (Bands 4 and 17)
- Model A1460*
- CDMA EV-DO Rev. A and Rev. B (800, 1900, 2100 MHz)
- GSM/EDGE (850, 900, 1800, 1900 MHz)
- UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz)
- LTE (Bands 1, 3, 5, 13, 25)
- Data only3
- 802.11a/b/g/n Wi-Fi (802.11n 2.4GHz and 5GHz)
- Bluetooth 4.0 wireless technology
so it shows clearly the difference , u can check the "part number" which's specified on the reciept
uk+ majority of other countries have the following part number : ME407 (plus country codes ,example:B or AE ,etc) , in USA model 1460 has the same part number (ME407 ) while A1459 part number is :ME401 which's not sold any where else but USA.
i don't know how u'll be able to solve ur problem but the reason why it's slow 's that this model won't be able to have LTE connection outside USA so it goes to GSM/EDGE connection which 's slower than the LTE.