That set of logo-less S4 and S5 episodes sounds like the unofficial Russian DVD release. (The easy way to tell is to check the language selection screen; if the spoken language options are english and german, and the subtitles are russian, then it’s the russian release.)

It’s compiled from the available english language PAL DVDs of S4 and S5 episodes (all those mentioned by thatguamguy above), plus NTSC->PAL conversions of the 9 episodes from the US Time-Life collection. It also has a further 7 PAL episodes from the french LCJ DVDs with the UK skits (which were missing from the french DVDs) patched in (1 DVD quality patch from a compilation video, and 6 patched from logo-free VHS), with the english language audio taken from the VHS. The remainder (including the Chris Langham episode) are from logo-free VHS recordings. There’s some jitter in the image, some dropout here and there, but they’re not bad for VHS transfers.

It’s almost, but not quite, sourced from the best quality that was available for S4 and S5 when it was compiled. The menus are all based on the official S1-3 sets and look quite professional. I think a lot of work went into that set, it was very nicely done.

The zoot tags are all wrong… but I’ll forgive him that. They’re hard to get decent sources for.