Thanks all, have looked at a few of the bigger importers but the prices are high. Yandles coming in cheapest so far but still a bit high (£1500+). That’s euro oak, can only assume English oak would be more.
The 7m section is the least important and could be done in 2 or even 3 shorter sections, it’s the ridge beam, carrying no weight.
Plenty of space here to set up a big bandsaw! Access not great though, we’re at the end of a narrow track, no artics.
I did consider chestnut poles, which would be hugely cheaper but don’t have the framing skills to deal with the round sections
Will check out the recommendations.