Starting with the original question , I would certainly consider an overtake there , but a lot would depend on the circumstances .
The fact that there were one , two or more cars to be overtaken would not neccessarily deter me .
One thing brought out in this case , it strikes me that many people seem to forget that , in an overtake situation , the vehicle doing the overtaking has priority , and it is the absolute responsibility of the 'overtakee' to be aware that they are being overtaken and to yield accordingly ; putting on a trafficator signal halfway through in no way alters this .
Having said the above , it is clearly unwise to overtake through junctions , past entrances where traffic in front might turn right , or where they already are indicating their intention to do so .
It is also the responsibility of the overtaking driver to make sure the other drivers are aware of him , to this end use of horn or headlamps is appropriate .
The police 'system of car control' , as taught in police advanced driving courses , and applied to every situation which can occur on the road , will take account of the responsibilities both as overtaker and as overtakee .
This incorporates multiple mirror checks ( to ensure you are not about to be overtaken before you make any change in position or speed ) , selection of the appropriate course , speed and gear to execute the manoeuvre , giving appropriate warning of your intentions to other road users ( and taking account of their reactions , or lack of reactions ) , whilst always having a contingency plan .
The below is the 'old' system which I learned in the 1970's ; I prefer it to the newer version and still use it .
From the perspective of the overtaker , the overtake might go as follows -
Closing on two slower vehicles , either see opportunity for an overtake , or hold back until one arises .
On deciding that overtake is 'on' -
Mirror checks ( to ensure you are not about to be overtaken yourself ) , select course which affords better view past vehicles in front ( at this point still not committed to overtake and can pull back in behind rear vehicle if eg front car is turning right or faster vehicle comes up behind ) .
Mirrors , signals & speed - further mirror checks for following traffic , signal if of benefit to another road user , select appropriate speed on approach to manoeuvre ( this usually takes account of slowing for a junction ; for an overtake it will normally at this stage mean keeping pace with the other vehicle )
Gear - select the most appropriate gear to negotiate the hazard ; for an overtake it will involve selecting the gear which offers the best acceleration over the anticipated speed range .
Mirrors & signals ( again ) check again for following traffic which may not have been there before , consider now giving a signal if one was not required earlier , or giving a supplementary signal to reinforce or emphasise one already given ( for example if turning right whilst also passing parked vehicles , a hand signal can be given to emphasise that you are indeed turning and not just passing ) .
Horn - consider whether any other road user is unaware of your presence and intentions : the horn or headlamp flash can be used here to draw their attention to you , but do look for a positive reaction before pressing on .
Acceleration - apply the correct degree of acceleration to clear the hazard .
From the other perspective , it ought to have gone as follows -
Intending to stop ahead in layby on the right .
Mirrors , select course ( check for following traffic , select course just left of the white centre line )
Mirrors , signals & speed ( check for following , or overtaking , traffic ) , give signal if it will benefit another road user ( right turn signal for following traffic ) , determine speed for manoeuvre ( in this case very slow for turn across the road ) and decelerate to arrive at that speed before the turn point , without braking excessively hard if close following traffic ( if you have left it to late and are at risk of being rear-ended , you should abort and overshoot the layby ) .
Gear - select appropriate gear for the turn ( may be a low gear if you have to move off from a standstill , or may still be your previous gear if you do not have to stop before turning and just braking to a halt in the layby )
Mirrors and signals ( again ) - as in previous scenario , but if at this stage you are being overtaken YOU MUST ABORT
Horn - unlikely to be used in this scenario , unless someone else occupying layby has not seen you
Acceleration - as appropriate to cross road , may just amount to lifting slightly off brakes then reapplying once in layby .
While that all sounds very long winded , in practice it only takes a few seconds and highly trained police drivers will become extremely competent and fluid in its execution . The civilian advanced driving organisations do teach the same system , but not usually to the same level of proficiency .
Although 'the system' is not taught to all drivers , the basic rules it is founded on do apply to all drivers and can be used against them when it all goes wrong .
I know that the unfortunate woman in the recent incident lost her family , and that my opinion may go against popular opinion as well as the court verdict - but I do feel that , no matter how ill-advised the overtake might have been , the main responsibility and fault for the incident was hers - simply because it is her responsibility to ensure that she is not being overtaken before changing course or commencing a turn ; also because , as I outlined above , overtaking traffic does have priority .