Buying joint presents can sometimes be difficult. Traditionally wedding/engagement presents were often something for the couples home, like kitchenware or appliances, but as living together is fairly standard before marriage these days, couples often already have everything they need in a practical sense.
Vouchers are always a good idea, as it means the couple can buy exactly what they want - although it does lack a little imagination.
Perhaps paying for them to go out somewhere could be a good idea. If they are into food you, could buy them a meal at a flashy restaurant that perhaps they wouldn't go to themselves. Or if they like to travel, a weekend away or flights to somewhere special could be nice.
I'm sure whatever
you buy them will be appreciated and special to them. Engagement
parties aren't about the gifts, it's about everyone getting together
and celebrating their news, so you being there will be good enough,
I'm sure!
