XK 2.8 Oil pressure sender thread size

Hi all,
I am replacing a defective sender for the oil pressure gauge and I need to know what the original thread size is (assume it is the same thread on the 4.2 as well?).

'69 XJ6 2.8, just brought back to life after some 30 years.

Greetings from Sweden!

1/4 British Standard Pipe Parallel (1/4 BSPP). At least it usually is.