You have a full plate verge fusee driven movement made and cased in Coventry. The cases were assayed in Birmingham and I think I can discern the date letter Gothic R for assay year 1840/41, which corresponds to the inscription - likely to be the name of the first owner. If I am correctly identifying the case maker mark - it appears to me to be most likely JH in an oval cartouche (inverted with respect to the assay marks) - James Heales, a mark registered in April 1834.
The finished watch will have delivered to the retailer, R Thwaites in Barnard Castle, County Durham, already with his signature. Given the watch paper carries the same name, this may be an original watch paper, but some collectors seek out papers to match the signature on the movement, so it is wise to be cautious in making a claim of originality.
The 'maker' of the movement is unknown but the frame was probably made in Lancashire, possibly locally in Coventry. A number of Coventry workers will have contributed to the finishing of the watch. This work may have been organised by a Coventry or Birmingham wholesaler who received the order from Thwaites.
1851 Directory listing
Value depends so much on desirability to a potential purchaser and the condition of the watch - impossible to give an accurate estimate from photographs. Most would sell for £100-£400. A service, which it will definitely require prior to use, with no or very little restoration work, would cost, if you can find someone to do the work, £200-£300.
In my opinion this type of watch is undervalued and while this is not an example of the highest quality, it is typical of its type which was been sold particularly in market towns across the UK in the mid C19th.
John