Renewing cooker cable - les than 5m run from CU to the cooker (45A)
outlet - run from a 45A MCB type 2.

This will be clipped direct to joists (1.5m) then buried in
cement/lime/sand plaster on a brick wall. According to IEE regs this
is installation method 1 + method 2, so cable rating ref method 1
applies.

IEE Table 4D5A shows 6mmsq cable has a max rating 47A for ref method
1. The voltage drop is 7.3mV/A/m x 5m x 45A = 1.64V or 0.7%.
Apparently OK so far.

But then a check on IEE On-Site Guide table 7.1 (conventional
circuits) shows a 45A radial circuit needing a 10mmsq cable. In fact
the highest rating table 7.1 can offer for 6mmsq is a 32A radial
circuit. Which rules out my 6mmsq cable.

Am I missing something?

I can see that 6mmsq would have the draw back of being run near its
limit, which is rarely a good thing engineering-wise, but that doesn't
explain why table 7.1 doesn't feature it.

Any comments appreciated.

TIA