I think it can cause awkwardness - mutual friends of ours were invited to the evening part of a reception which was held on a Wednesday on the other side of the country (UK). We had been invited to the whole thing and they're good things so went, but our mutual friends didn't (unsurprisingly). To be fair, said mutual friends had invited the wedding couple to the evening do of their wedding!
I think the evening reception invitation ony works where the invitee is local, and e.g. colleagues, in the situation where there's a large friendly office, but no one person that can be invited above others.
It may be just my own impression, but gifts just don't seem to be as big a deal in the UK generally. I do give wedding gifts (BF and I have a set budget which we spend on every wedding couple), but I've never given an engagement gift, definitely not a shower gift (never been to one!), asked any of my friends what they've received, or had them even mention gifts to me (apart from when I asked for the wedding list). I rarely give/receive birthday presents as well, apart from v.close friends and family.