Chinnor slipped into the National 2 South relegation zone with a disastrous 43-12 defeat away to Bishiops Stortford on Saturday.
With struggling Launceston earning five points from their 27-23 victory over London Irish Wild Geese, Chinnor are now in the bottom three with one game left.
They started brightly with Matt Goode converting his own try to put them into an early 7-0 advantage The home side responded with tries from Tom Banks and George Cullen to lead 12-7 at the interval.
Early in the second half, Goode went over for his second try to level the scores and the match was in the balance.
The rest of the match was dominated by Stortford who added further tries from Sam Winter (2), Chris Aldam and Nick Hankins to leave Chinnor in big trouble.
Henley slipped into the relegation zone in National 1, when Cinderford gained a 17-9 victory away to Albanians.
South West 1 East champions Oxford Harlequins topped the 1,000 points mark for the season as they ended a successful campaign with a 33-21 defeat away to 14-man Windsor.
The teams were drawing 11-11 at half-time, with Quins’ points coming from a try by centre Keni Fisilau – after a neat grubber kick from winger Jack Robinson – and two penalties by Will Hilton.
Chris Laidler landed two penalties for Windsor, who levelled the scores through No 8 Simon Evans, after Quins’ flanker Richard Battson had been yellow-carded.
Windsor raced 19-11 ahead with a try by prop Ben Louission and a penalty by Laider, despite having flanker Tom King red-carded and winger Sam George sin-binned following a flare-up.
Fisilau’s superb second try, converted by Hilton’s touchline kick, made it 19-18.
Quins had their own disciplinary problems as hooker Simon Chadbone and prop Pete Bolton were sin-binned in the second half.
Evans’s second try and Laidler’s conversion were answered by Hilton’s penalty as Quins trailed 26-21.
With the final move of the game, prop Alex Williams drove over for a try, Laidler converting to give a flattering scoreline to Windsor.
Witney wrapped up fourth place with a 34-14 win at Swindon.
The visitors took the lead with a drop goal from fly half Phil Thomas.
And they kept up the pressure when left wing Carl Strutt charged over for an unconverted try.
However, Swindon hit back with a try from Adam Westall, which he himself converted.
The visitors stretched their advantage when Charlie Bennett combined with Henry Lamb before releasing Ted Landray, who scored on the right.
Witney made it 16-7 on half-time when Landray kicked a penalty.
The visitors went further ahead when prop Jamie Burke crashed over from a ruck, following a break from scrum half Gareth Campbell.
Landray slotted two penalties in quick succession for a 27-7 lead.
The hosts had two players sinbinned, but replied with a converted try.
However, Witney then put their foot back on the gas, with full back Matt Clarke scoring a try and Thomas adding the extra points.
Hosts Didcot came back from 7-15 down to beat Crowthorne 21-15 in the BBO Championship.
Didcot’s tries came from skipper Sam Lacy, Barry Llewellyn and Ronnie Booth, with all of them converted by Josh Witts.