Here is what I read:
- We are great
- Client not so much
- They don't like us
Pro-tip, sometimes it better to be liked than right. Who do you want to be friends with more, the boss man, or the workers? Boss man pays the bills so always be his friend. But sometimes it helps to be friends with the workers also.
So instead of "Us" versus "Them", try to make it "We".
Rule #1: BE NICE
I'm sure you are always very professional, but from what you said in your post, I'm doubting you are always nice.
Sometimes a friendly visit to the client, box of donuts/candy/meat-veg tray/ice cream/movie tickets/etc... can go along way. Basically say, "we want to get along, we want to help you, we are on your side."
This isn't so much a reward, since it doesn't sound like you are in a position to reward or punish. Its more about trying to change the perception of the other team about you from "they are our enemies" to "they are our friends".
Rule #2: Be in control
SVN? Really? IfIf I was manager in this situation, I would say, "how can we manage the code better". Does Github let every Joe Haxxor commit their craptastic code the master repo? No. If
If possible, I'd maintain a separate Git repo, where you can add their contributions as separate pull requests. If they are stuck on SVN, so be it. You can give them your contributions as big single commits. Even if you have to move the code manually, its better than the client team screwing up the repo your team depends on.
Don't let their bad commits and bad SVN practices control your productivity.
Also, like the other posts said, document communications in case you need to CYA.
Good luck!