Head bolts

I’m about to change the 300tdi in my defender for a known good discovery 300tdi. The only snag I can see I’m going to face is the air cleaner housing needs to be bolted through the head bolts and isn’t on the discovery engine. What’s the opinion on here? Can I get away with removing two bolts and fitting the air cleaner then re torque or do I remove the head, have it skimmed and refit with new head gasket and head bolts?

Your opinions on a postcard please.

If the engine is running well I'd look for another option rather than disturb the head. There are a few other things bolted to the block - on the 200 tdi there's an inspection panel beside the injection pump with 4 well sized bolts holding it on. It would be easy to fabricate something to use those.