Further bus chassis were bought, with YBS building the bodies themselves at their premises in Manor Road, with interior finishing by a local firm, J. Mussell and Son.
A key figure in the company by this time was traffic manager Arthur Bowden, who also acted as signwriter, mechanic and handyman.
By 1927, A&D were operating a high intensity Stoughton service with a flat fare of just one penny, with the clear intention of putting YBS out of business.
The firm was at a low ebb but Hayter, fighting back in a "make or break" move, invested in 2 new Dennis 'G' buses for a route in 1928 from Guildford to Camberley, also in competition with A&D.
That year a third Dennis bus enabled the start of a service from Guildford to Farnham via Compton, Puttenham and Seale.
In 1938, YBS produced an illustrated brochure, "A Yellow Bus Journey", extolling the beauty of the countryside between Guildford and Farnham and suggesting visits to the Watts Gallery and Watts Mortuary Chapel en route, or using the service as a stopping-off point for walks to Frensham Ponds, Crooksbury Hill, Waverley Abbey and other landmarks.
Women were employed as conductresses for the first time, and loan of a Dennis Lancet to the Ministry of Supply (and its subsequent return in unserviceable condition) meant that YBS had to hire vehicles from other operators such as Tillingbourne Valley Services to cover for unserviceable buses, a situation which was eased by purchase of two Bedford vehicles from a company in Dover.
In 1953 Yellow Bus Services was incorporated as a limited company, with Hayter's widow as the principal director.
In an attempt to increase revenue by diversification YBS built a petrol station on their premises in 1955; this aspect of business expanded over the following years to include car repairs, tyre, battery and accessory sales, together with a paraffin delivery service.
A club room was provided at the bus garage, fitted with a TV and sporting facilities, and regular social events were organised.
This resulted in an incident in 1957 during the national bus strike (through which YBS continued to operate) when a Yellow Bus en route from Farnham was "held-up" by 20 militant union members from the Aldershot and District company, who prevented the driver from continuing, and deflated his vehicle's tyres.
The only serious accident to befall the company occurred on 2 September 1952 when the Farnham to Guildford service was involved in a collision with a lorry near the Princess Royal pub at Runfold.