I’ve been on a similar grad scheme and have had the following experiences:
1. When asked to do placements, they always paid expenses. As stated above, how can they expect you to run two homes and cover the additional cost of working away from your normal office.
2. They asked me to do an overseas placement at a time that didn’t suit me personally (ie: right through summer and I’d just met a fine lass, with whom I now have two fine children). I just said no, sorry I’m not going and told them why.
My advice is stand firm and do not cave in. If they try and bully you into it, you still stand firm and think about if you really want to work for such a firm.