can c4 players prevent transposition?

With a 1500 rapid rating here, and probably no more than a 1500 OTB rating, I'm telling you for certain that this transposition will have no impact on your results in your upcoming tournament. 

Instead someone blundering a piece will. 

If you want to avoid transposition though, I'd recommend 2.Nf3 d5 3.e3 Nf6 4.b3, where you develop the Bishops to b2, e2, Nbd2, 0-0, and play d3 at some moment. This is a solid setup for white, and it's almost universal against everything your opponent does:

A 1.c4 player should be ready to transpose in any Queens pawn opening, especially after 1...e6. If you want to play for an opening advantage you should learn the transpositions otherwise your second move compromise your opening anyway. The Tarrasch defense it's a favorable opening for a 1.d4 player since the pawn structure with a isolated d5 pawn favors Whites endgame. For that reason it's not so popular as ratings goes up!

that makes sense I usually fianchetto kingside in response to unusual c4 responses but I guess that's less flexible. UDCF tandard is like 1560 but my rapid is 1697?! not sure why. I abandon a lot of chess.com games so I'm probably a little better than 1500 but what you say probably applies to anyone who isn't at least an expert

Easy. Don't play d4.

+1. Since the pawn structures of 2 openings are different, just don't make any pawn moves that could make the transposition possible.

I'm thinking of something like this

I think you'll have to be comfortable with e.g. reversed benonis or benkos though.

Or play it like a reversed hedgehog like cherub shows.

Although... maybe the best option is learning how to play the positions you hate. That way you don't hate them anymore. I'm guessing the OP doesn't like them because it's a gap in his knowledge. 

Ludicrous or,  at least, a huge exaggeration. Do U really pretend that the English opening: Agincourt defense 1. c4 e6 reduces to the Tarrasch defense ?!?

Your going to have to figure out what 2nd, 3rd, etc. moves keep your system as English as possible, but you're not going to stop the transpositions. 1 c4 c6 and 2 d4, 2 e4, 2 Nf3 or 2 Nc3 and you're still likely to face a Slav or Caro-Kann Defensive System.  Check out the options of the Opening Explorer and see which 2nd, etc. moves gives you the positions you most want.

There is a total alchemy in chess and, in principle and sufficient depth, almost everything can be transposed into almost everything. There is the final common successor: any position with only 2 kings on the board.

You can try the symmetrical Tarrasch:

Or you could try 6.dc in the main line:

I don't really know what else you can do here.

Yeah, I'm not sure why I didn't ask this before.. but just why are you afraid of the Tarrasch? It's not particularly easy for black to play, and white often just gets some nice permanent advantages. 

I just assumed he didn't want to play against a isolated pawn.

Perhaps, although it's a situation that you need to know how to play, since it occurs often, and also white has an easy target, just following the fianchetto variation. 

It's cuz the name Tarrasch sounds brutally! It can give the desire to rush out!