The visitors were soon on the scoreboard as Will Robinson slotted an early penalty but TJs, as in previous weeks, found their line-out was not functioning well.
Henley took advantage of a long spell of possession to mount a prolonged pick-and-drive attack which allowed prop Brad Cook to score a converted try under the posts. Robinson scored another penalty but fly-half Ben Bolster responded in kind.
The home side then turned over the ball, broke through TJs’ line and made good ground for No 8 Alex Bradley to cross for Henley’s second try, which Bolster converted.
At 17-6 down TJs suffered a further setback when centre Finlay Coxon-Smith was yellow-carded for an offence while resisting an attack but they hung on until half-time.
In the second half it was Henley’s turn to lose the ball and from the halfway line some slick and accurate passing involving full-back Toby May and centre Duncan Tout sent winger Hugo Watson in for a try in the left-hand corner, though the conversion was missed.
TJs were showing a degree of dominance in the tight and the pack appeared to have successfully pushed over for a try.
After consultation the referee signalled a penalty try for Henley having collapsed the scrum and suddenly TJs were in the lead at 18-17.
The closing stages were nerve-racking and littered with penalties and handling errors by both sides, any one of which may well have turned the game again but no further score came.
Tonbridge stretched their lead at the top from one point to four – Henley having secured a losing bonus point.
TJs now face another stern test when they travel to fourth-placed Redruth on Saturday (February 8, kick-off 2pm).
