Project running Motor Drive board and servo board. How? I2C I think?

I've got a new project I'm trying to do, a 4 wheeled chaise with a 6 servo arm and grip controlled by IR. My pre thought was the drive the wheels with the CHI035A High Powered Project Board and have the IR input through this board, and then run the servos with the SD21 servo board. but how do I get the two board to take to each other I know the SD21 can handle I2C and has 3 I2c connector on board. but how can I control it from the Motor Drive board when I an already using B4,5,6,7 to drive the motors. what am I missing or do wrong, or do I have to run a different board to drive my chaise and IR input.

The three immediate options I can think of are -

1) Build your own similar-to-CHI035A board as a genuine PCB or on strip-board using more suitable I/O pin allocations.

2) Modify the actual CHI035A to reallocate the motor drive to other I/O pins.

3) Use software bit-banged I2C to control the SD21 servo board.

Thanks so far...
Option 1) to complicated at this stage, only have facilities to make single sided board at the moment and it take to long to get someone else to do it.

2) I think I could move B4 to either B2,3 but need to get another board, not testing on the only one I have.

3) sounds good but sure how to yet, are the any examples around on how to?

Here's some old example code for the 08M but it should be possible to modify it for the PICAXE-18M2 and others.