Dukascopy spot data is always given as GMT. They say that their prices are bid prices from a variety of sources, therefore the price spreads on each bar are wider than you would expect for bids. I have tested their GBP data for 1 month now against actual Globex trading with a very close PnL correlation on all 18 trades, even though one is spot and the other is futures. I have checked the data against FXCM /NetDania charts, which are bid prices, and the values seem to be very similar. So far they've got my thumbs up for backtesting, although it's a shame that the data is not longer term.
I've looked at the free sources fin.rus and dukascopy
However can anyone shed any light on:
1) What time are they based on? GMT? Russia?
2) How accurate are they?
Yes I had the same problem ! I take 07:59:59 to refer to the bar starting at 07:59:59 GMT. I'll be interested to see how you get along using this data. I tried the scmagic data for GBP futures, but in the absence of bid & ask, found it rather too bitty for my purposes when volume on the futures is thin.
I'll give dukas a go for some other pairs then.
Pity its GMT and not British time as it means I'm going to have to perform some hour shifts!
I've also noticed the time is 07:59:59 for example as well. Is this the end or start of the bar?