Both of them are really great. Hard to choose between them to be honest - 'Pendulum' has that fine, quirky reed work by Dave Tomlin whereas 'Trio' has an incredible atmospheric feel of great concentration on tracks like 'Abena'. It was not for nothing that they opened the 2005 'Jazz Britannia' concert at The Barbican with that very number - played solo by Matthew Bourne - and played pretty well verbatim. It stunned the house (well - it stunned me, for sure).
As for parallels - I think Jan Johansson in Sweden was covering similar ground - possibly with more of a 'folk' angle. The Nordic connection is an interesting one ! 'Atmospherically knotty' - spot on, Clifford !
The one album major Lansdowne I don't have and am looking for is Amancio D'Silva 'Integration' (although I have it on CD - if you see a nice copy let me know). Have all of the Rendell/Carrs and 'Hum Dono' on LP, although the vinyl on my 'Shades of Blue' is far from mint. It's a beautiful album though and fortunately the sleeve is immaculate. I just need a mint LP with a gash sleeve now..