Flyer 719, earlier in this thread Jetdriver noted that V1 is not a distance but a speed. Thus in your example at LCY, apart for the 146/RJ having a choice of 3 (some aircraft 4) configurations for take off, all with different speeds, the V1 speed can still be adjusted for wet / dry runway surfaces for all other unchanged conditions.
In non-limiting operations in the 146/RJ, (V1=Vr) we were taught to use a 10 kt split V1 … Vr; this reminded us that there are differences between wet and dry operations. On the other hand in the 146 the bugs had to be a split as they could not be overlaid on the same value, this also sequenced the crew calls of V1, and Rotate.
Most 146/RJ operations were ‘turboprop’ like; thus relating to the original question, the 146/RJ SOP was to abort for ‘anything’ up to 80 kts and after which only engine failure or fire. The RJ incorporated MWS inhibits using this logic, thus above 80kts the crew will only here the fire bell. ‘Anything’ was generally defined as double system failure or any aspect of similar consequence; a dual system failure after 80 kts is still safe for flight.
In recent years industry RTO training focussed on the problems of ‘what if the aircraft could not fly’? This stemmed in part, from several well published aborts beyond V1 where the crew perceived an engine failure as a bomb; note no such bomb events have been recorded and the probability of such an event occurring at or about V1 should be dismissed as extremely remote. The other aspect was the concern of control, but as has been seen in many accidents the problems appear to be due to something other than a control block. If the aircraft rotates it should fly (sooner or later); if it does not rotate then it is most unlikely to fly. Safety is ensured from correctly executed pre flight checks and good maintenance to ensure the serviceability of the split controls design certification criteria; if so then a control jam at or about V1 is another very remote event that crews should not burden them selves with. My advice to south coast is to concentrate on the simple aspects of an engine/system failure – the Go / No Go boundaries and follow well practiced procedures for continued take off.