Getting to Heathrow T3

[Maurice]

Need to get passenger to H'row T3 early Tuesday morning.

Garmin satnav proposes long-winded/busy route M25(exit 15) to M4, then
across and down into airport.

On the map, there seem to be 3 preferable routes:

(1) Off at M25J14 --> flyover towards T5, 1st left at 1st roundabout onto
Western Perimeter Road and
round to the right to enter tunnel into T1-2-3).
Question: Is 1st left at that roundabout permitted?
If not, any other problem with that route?

(2) Off at M25J14, take 2nd exit onto A3113, at next roundabout take 2nd
exit on S.Perimeter
Road towards T4, then at 1st roundabout take sharp left 1st exit onto
Western Perimeter Road,
then as (1) above.

(3) As (2), but at 2nd roundabout take 1st exit from A3113 onto A3044 up
to T-junction (lights), then
right onto A4 and then right into airport.

Of the 3, (1) seems the neatest and simplest, but the one time I tried it
I must have missed the 1st
turn at the 1st roundabout, because I unavoidably finished up having to
get through the T5 drop-off
area before then keeping right to join the Western Perimeter Road!

Then the $64 question is, how does one set a Garmin Nuvi 2547 to follow
any of the above routes?!
(Tried Apps/Trip Planner, but would not offer Stanwell/"Western
Perimeter Road".)

[Maurice]

Post by Maurice
how does one set a Garmin Nuvi 2547 to follow
any of the above routes?!

Finally found you can ask it to find all "Western Perimeter Road"s and
then choose which town's to use.

W.r.t. to the 3 routes, it does take the 1st left at the roundabout at
the end of the flyover to T5 from M25J14, onto the perimeter road
(which there it calls "Wright Way"), so the SO will give that a try.

(Also found the same thing can be arranged on a TomTom XL.)