If the drive-side cup is "reverse threaded" it is almost certainly English. The 70 mm shell width can be handled in one of three ways:
1. As you mentioned, buy a 73 mm bb and add spacers.
2. Have the bb shell faced by your LBS to remove the extra 2 mm and use a standard 68 mm bb.
3. Find one of the Shimano UN-series bottom brackets that has a metal nds cup. These don't have a lip on them and can be threaded into the bb shell past flush until they bottom on the cartridge itself.