All MCBs of the same BS number, rating and type letter (e.g. BS EN 60898 32Amp typeB) are electrically equivalent, but different manufacturers and often even the same manufatcurer across different ranges are not physically or dimensionally the same. There are several dimensions that must be identical for them to be interchangable. Some MCBs are compatible with others, most are not. There is more to this than meets the eye. With all due respect and the best intentions, the question is not really one that would be expected of someone with sufficient knowledge to do this job safely. I agree with J, follow Peccavi's advice.
Steve, November 2009