If you think that low floor double deckers are a product of the 1990s and that multi-modal through ticketing started in the 1970s, read about DFB 43 and you will discover that Merseysiders were enjoying the benefits of both of these innovations in the early 1960s.
Crosville DFB 43 (256 SFM) was delivered in 1961 and was allocated new to Heswall depot. It was one of fourteen Bristol / ECW FLF6B 70-seat Lodekkas which were Crosville's first double deckers to the then maximum permitted length of 30 feet. Although double deckers of this size had been permitted since 1956, Crosville had continued to favour shorter (27ft) Lodekkas up to and including 1960, these being rear-entrance 60-seaters. The FLFs broke further new ground for Crosville by being their first Lodekkas with forward entrances. Conductor operation was still the "norm" in 1960 and this had a bearing on the repositioning of the entrance. The reasoning was that the driver would control the electrically-operated entrance doors, allowing the conductor to concentrate on his now harder job of collecting fares from the increased number of passengers.
These early FLFs (DFB 40 to 53) had Bristol BVW engines and four speed crash gearboxes. Other Lodekka operators specified the alternative Gardner 6LW engine, whilst a further option was a five speed gearbox. The FLF was actually an early example of a low-floor double decker. Once a passenger had stepped from the pavement onto the platform, all 24 forward facing seats on the lower deck could be reached without needing to negotiate any further steps.
Along with Lancashire United and Ribble, Crosville was one of three major companies running into Merseyside. By the 1920s there were Crosville depots at Liverpool, Heswall, Birkenhead and West Kirby, all four of which lasted into the MPTE era. Several Crosville depots from outside Merseyside also operated routes into Liverpool or Birkenhead, namely Chester, Denbigh, Flint, Mold, Runcorn and Warrington. The West Wirral town of Heswall was not on the Wirral electrified rail system but, nevertheless, many residents worked in Liverpool and Crosville's Heswall depot consequently had a very heavy commuter flow into Birkenhead, where passengers changed to ferries or trains to complete their journeys. This initial delivery of FLFs was allocated en bloc to Heswall, where their 70 seat capacity was most needed. The two main corridors were the F22 & F23 via Barnston and the F19 via Pensby, whilst Birkenhead Corporation had a share of the traffic with their 71 & 71A via Irby which used 66-seat Leyland PD2s. Of these, the F19 was the most direct and therefore the busiest. Crosville and BCT both offered "bus-and-boat" weekly tickets in conjunction with Birkenhead Corporation Ferries, an instance of transport co-ordination on Merseyside that long preceded the coming of the PTE.
In the 1970s the MPTE inaugurated a direct Heswall to Liverpool service (Rapidride 418/419) using one person operated Bristol RE single deckers operated by Crosville. This ran via the M53 and the Wallasey tunnel, neither of which existed when DFB 43 was new. Such was the popularity of the Rapidride that the PTE prevailed on Crosville to introduce one person operated double deckers. These materialised as Bristol VRs and, as more VRs were added to Heswall's allocation, the FLFs were moved elsewhere. DFB 43 was reallocated to Rhyl, where a 70-seater was needed for a contract. Following withdrawal it swapped Crosville green for a different green, being sold to Castrol Oils for use as a staff bus, ferrying workers from Birkenhead to their plant in Ellesmere Port. From Castrol it went into preservation.