Neil,
Those caps are there to serve to block dc voltage from the output of your DAC. The Resistor is there to provide a load for the DAC. That resistance, 100kohms, is in parallel with the impedance of your amplifier (which is dc coupled, so you definitely need those output caps on the DAC.)
The DAC chip(s) is fed with a Va of 8.4vdc single rail, so the output of the dac is sitting somewhere between 8.4vdc and 0vdc, roughly 4.2vdc. (the dac designer prefers 3.85vda as optimum and provides instructions for optimizing).
You don't want to feed your dc coupled amplifier a signal with a dc bias, so the cap is there to eliminate the dc. [always turn on the dac prior to your amp, to minimize and 'pops']
The 100uf electrolytic is definitely overkill in terms of capacitance; the designer personally prefering a .47uf $$$Mundorf silver in oil cap.
I'd personally prefer about a 2.5uf cap to allow for the possibility of powering a lower impedance amplifier while maintaining bass performance, but remember that all things being equal, the larger the cap, the higher the price.
Arguing personal subjective preferences in capacitors is like discussing religion with strangers; inevitably you'll say the wrong thing. Nor am I conversant with your listening preferences or exhaustively what is available in Europe. The Wimas, either singly or paired, should be fine, but I wouldn't know if they'd be your cuppa. Low in cost, but with some audiophile credibility (FWIW based on no personal experience) are the Amp-Ohms available from RS and the ICW Clarity caps which are made in the UK. Your potential choices for the output coupling cap(s) range from SCR, Wima polypropolenes... on the lower cost end upwards to Mundorf Silver/Gold foil in oils, Audionotes, or Teflons. THAT is a subjective call.
