Will I able to get a first

Only year 5 and year 6 Count for the overall grades
The total credits is 180 each module is worth 20
100 credits from year 3 do however have to count

The percentages I got were:
Year 5
70%
75%
56%
62%
64%
65%

Year 6
70%
40%
65%
80%
78%
72%

Not sure what you meant by "100 credits from year 3 do however have to count" - do you mean at least 5 modules in Year 3 need to be passes?

If each module is worth 20 credits and there are 6 modules per year, that comes to 120 credits per year. Do you need to include a dissertation for 60 credits somewhere?

I can calculate the average grade based on the marks above, because they are all equally weighted.
Using final grade = (grade1+ grade2 + grade3+...)/12
grade in progress = (1/12)*(70% + 75% + 56% + 62% + 64% + 65% + 70% + 40% + 65% + 80% + 78% + 72%)
= 66.417...%
This is an upper 2:1. It's a decent grade.

I'm a little curious to what you are studying though.

I'm studying law, we didnt have a dissertation but for the overall classification they only count 180 out of 240 credits so it's kind of that they count your best marks. But 100 out of the 180 credits must be level 6.

I'm studying law, we didnt have a dissertation but for the overall classification they only count 180 out of 240 credits so it's kind of that they count your best marks. But 100 out of the 180 credits must be level 6.

Taking your 100 best level 6 credits (in red) and your remaining 80 best credits (in blue):

Year 5
70%
75%
56%
62%
64%
65%

Year 6
70%
40%
65%
80%
78%
72%

Averaging these gives (70+75+64+65+70+65+80+78+72)/9 = 71%.

Is this the calculation you mean?