Two Penny Blue Information

Hello
Could anyone here possibly add some detail to this two penny blue I have pictured?
It has the letters in all four corners which makes it 1858 or 1870 and that's as much as I know
Anything else would be great
Thanks
Simon

In my opinion it is Stanley Gibbons SG 45 plate 9. the White line above the "two pence" is thick. You can see the plate number 9 in the border opposite the lips and level with the bottom of Her Majesties bun (in English a Bun is hair gathered into a cluster at the back of the head. So you Americans just calm down!)
I'm not an expert at identifying QV GB stamps but it's what I collect and it's where it would go in my Album. Hope this helps.

Nice bun.

Thank's Noocassel,that's great help