Mobile selection help topic

Please help
I want to buy a mobile for around 25k
Which one should I buy
-canvas knight
-Gionee elife e7
-galaxy grand 2
-moto x
-sony Xperia z

[Q] "Band Selection" in service menu topic

I'm tempted to change this, but should I?

I have the F320K and I got into the service menu using 5457#*320#, then into the WCDMA service menu where I can see "Band selection".
In here, it has all the GSM and WCDMA bands selected, but nothing under LTE (it has B1, B3, B7 and B8 as options).

My brain tells me this is stopping me from using 4G here in the UK, but would I be okay enabling B3 and B8 in this case? (those are the bands the K variant is advertised as supporting).

Please help, I don't want to kill my nice new phone. :)