Why do you find that so hard to believe ?
I cannot see why Champion, for instance would manufacture this range:
Champion 300, 8415, 9FYSR, N10Y, N11YC, N281YC, N66Y, N79Y, N89GY, N8Y, N9Y, N9YC, N9YCC, N9YCX, N9YX, OE001, OE001/R04, OE001/T10, OE22, OE22/T10, OE109, RN11YC4, UN79Y, stk300, stck302, stk322.
If they were all exactly the same.
And they are not all exactly the same, then they are not all an exact replacement for a NGK BP6E, are they?
EDIT:
Got word back from Champion.eu, they say they have no details of Royal Enfield EFI bikes but by cross referencing, they have come up with Champion OE081/T10
Frank