Possibly. Its clear that there was a lot of caution, nearly all the submissions had an associated flying scale demonstrator(s):
Armstrong Whitworth A.W.52 - arguably became a demonstrator for the A.W.56 design
Avro 707 - one-third scale of the Type 698, 2 ordered June 1948 but eventually 5 built due to cancellation of the 710 (707 FF 4/9/49 - 3 years before the 1st proto 698 on 30/8/52; 707A FF 14/7/51, 11 months before 698)
Avro 710 - half-size scale of the Type 698, 2 ordered June 1948 but cancelled in Feb 1949 (though work stopped around Sept 1948) as not needed as some 698 features could not be incorporated
Bristol Type 174 - four-tenths scale of the Type 172, 2 ordered in May 1947, later cancelled,
Bristol Type 176 - three-tenths scale of the Type 172, nearly ordered as a swept-wing research aircraft in its own right
Handley Page H.P.87 - scale glider of the H.P.80, never built due to desire for a powered aircraft.
Handley Page H.P.88 (aka GAL.63, aka Y.B.2 aka Supermarine Type 521) - two-fifths scale of the H.P.80, 2 ordered in July 1948, only 1 completed (FF 21/6/51, crashed only 2 months later after 14 flying hrs - 18 months before 1st proto H.P.80 on 24/12/52)
Short S.B.1 - glider for the aero-isoclinic wing for the S.B.1 (re-use of designation), 1 built (FF 14/7/51) and later rebuilt into S.B.4 Sherpa
Short P.D.10 - high-speed transonic aero-isoclinic wing, based on Swift fuselage, technically not for S.B.1 as not proposed until 1953 but likely to have been needed sooner had the S.B.1 been selected, never ordered
The only designs submitted that didn't need scale demonstrators were the more conventional designs; EECo B.35/46, Short S.A.4 and the Vickers B.35/46.
Its too easy when discussing the four V-Bombers to ignore this host of aircraft, this was a large R&D effort and far more extensive than just the bombers. A lot was at stake, in some ways British post-war aerodynamic development was tagged onto the B.35/46 entrants (and doesn't include the delta-wing research aircraft like the P.111 and F.D.1 and F.D.2 linked to fighter research and the cancelled AW.58 and early 1950s VG-wing research types).
There are also the NBC/NBS testbeds; the two Sperrins, a RRE Hastings conversion with H2S Mk.9 and the Avro Ashton conversions for visual and H2S blind-bombing research.
The S.A.4 had been designed to the long-range 5,000 mile draft requirement (OR.230) and the smaller 4-engine version selected as the interim bomber as soon as November 1946 - its buried engines giving way to the two mid-span nacelles. In January 1947 Spec B.35/46 (OR.229) for a medium-range bomber was issued. In March 1950 the MoS wanted to cancel it due to the Type 660 Valiant now being in development (selected July 1948). But they wanted the two prototypes for flight testing which they hoped would bring V-Bomber service readiness forwards by 18 months. £1.15M had already been spent, Shorts needed £870,000 to complete the prototypes and even if cancelled, about £300,000 would still need to be spent on make-work for Shorts until something else came along - so the Treasury released the extra money. Despite such a head start, the prototype Type 660 flew 3 months sooner than the first Sperrin!
In hindsight the selection of the 'Interim Bomber' based on the larger OR.230 bomber in late 1946 seems a mistake, the Air Staff rejected the long-range jet bomber and felt medium-range was far more practical even if advanced aerodynamics were required. Even Shorts had another roll of the dice with the S.B.1. It would have been better to have let B.35/46 take its course and then pick the Type 660. Given Shorts had a 20 month advantage over Vickers to work on the Sperrin there was no corresponding urgency to show any advance in the first flight date or development, it wouldn't have appeared any sooner than Valiant in frontline use so with hindsight the selection seems a waste of time and money. Waiting 20 months wouldn't have hurt the Air Staff at all.
