we advertise our horseboxes / business fortnightly in H&H - the reponse rates fluctuate due to time of year - its quiet at the moment - we tend to find, horsequest, horsedeals and horsemart to be pretty good too., horsedeals we get great response rates from.
H&H is expensive but for private sales / buyers it is the most read medium and is quite possibly the first port of call for most buyers when looking for a new lorry.
Yeah i have done Horsemart & Horsetrader. Forgot about horsequest, thats where i got my trailer form. Personally my first port of call in Horsemart then H&H. Obviously i dont mind paying if it sells!!!