It looks like WCML intermodals are being diverted via Nuneaton / Leicester / Peterborough where required; for example the schedule for 4L67 Trafford Park - Felixstowe has been altered to run via Peterborough on 29th/30th December.
Daventry should still be accessible from the north. If 6M45 (Dollands to Daventy water train) runs on these dates, it has an interesting diversion via Redhill / Wembley / Bletchley / Bedford / Wigston / Nuneaton (passing at 12:23) / Walsall / Bescot.
Being in between Christmas and New Year, there will be less freight traffic than normal, but it varies depending on the type of freight. Aggregate services are quite likely to be cancelled for example - although I'm not sure about HS2 stone - and some factories like Halewood might shutdown over Christmas & New Year, but intermodal may be less affected and domestic intermodal to Scotland is likely to run to keep the supermarkets stocked.
You can view the freight schedules on RTT, but just because something has a variation schedule re-routing it, doesn't necessarily mean it will run!
https://www.realtimetrains.co.uk/se...0/1000-2000?stp=WVS&show=all&order=wtt&toc=ZZ
