Boy - this is one of the hardest ID posts ever! I don't have any magic answers, but can provide some input. Here goes:
For the images you've provided, and location information, we're choosing between:
Knapweed Fritillary
False Heath Fritillary
Assmann's Fritillary
Nickerl's Fritillary
Heath Fritillary
Asian Fritillary
Cynthia's Fritillary
I think the last 2 can be ruled out, even on a cursory glance. Based on the underside markings of the first 2, I'd also rule out Assmann's and Nickerl's for these (there is normally a slight colour difference in the 2 outermost cells on the hindwing underside.
Knapweed Fritillary has a distinctive row of orange cells on the hindwing upperside, bordered by rows of paler cells. This rules out 4 and 6. And the underside has something similar - although the same cells have darker-coloured centres - ruling out 1 and 2.
False Heath Fritillary has a characteristic multi-coloured arrangement in the first row of coloured cells in from edge of the the hindwing underside. This rules out 1 and 2.
So this leaves:
1. Heath
2. Heath
3. Heath, Knapweed, False Heath, Assmann's, Nickerl's
4. Heath, False Heath, Assmann's, Nickerl's
5. Heath, Knapweed, False Heath, Assmann's, Nickerl's
6. Heath, False Heath, Assmann's, Nickerl's
My "default", by the way, would be Heath Fritillary, given its distribution and population.
Over to Guy
Cheers,
- Pete