Insulating door, window frames and dry lining

Does anyone know if the above can be done? At this stage the cavity walls have been filled and loft insulation topped up.

The windows are fitted with low 'E' sealed units but what about the frames? These are extensive i.e many windows including a large bay and the frames are uPVC and not insulated. Is it possible to have the frames 'pumped' with insulation in a similar fashion to cavity walls?

I am also thinking about internally insulating the external walls.

Also, is it possible to get an insulated wooden external door?

Does anyone have any experience or advice to offer on any of the above-mentioned?

Thanks in advance.

Your pvcu frames will not require insulation in between as they are multi chambered giving air pockets between for insulation.