Agree - #1 bayonet filters and hood. In the heyday of Rollei, numerous manufacturers made filters to fit Rollei - some of these used mounts which unscrew easily into 2 parts. I have made myself a "new" yellow-green filter by removing the glass from a B+W 35.5 mm filter and putting it in one of these mounts. B+W used to make Rollei bayonet filters, haven't seen them for a while. Filters are available new from
www.srbfilm.co.uk but these are resin types.
CLA - no problem for any competent tech. I know good people in the UK - will give you addresses if interested.
Most Rollei products were really well designed, but not the ERCs. These neded to be stretched to get the camera in, as a result an ERC which does not have ripped stitching is almost impossible to find. They are quite impractical, but could be repaired by a leather shop if you want to try one.