Gear shifting problems on Boardman XC Team

pgpeter123

I bought a second hand Boardman XC Team Road Bike (?) 2014(?) a little while ago and immediately had problems with the gears, both front and rear cogs ( sorry, but after 70 years of life I am no more mechanically minded now, than I was 60 years ago). At Halfords I asked if it was worthwhile doing all the work they recommended and they said yes, to £180 expenditure, onto the £120 I had paid for the bike.
Well they basically replaced everything, but gear gear shifting is a problem, particularly changing down when you need it most. I assume that the gear shifter when pulled towards you changes to a higher gear and this generally works, but a pull/push to the left only occasionally drops down a gear, more often it goes to a higher gear. Yes, when I am able to (in the present crisis) I will go back to Halfords, but it was last year when I had the work done. Any advice?

The Rookie

Indexing the gears for consistent shifting isn't hard.
It's normal for new parts (especially cables) to settle slightly and need a tweak.
You need to use consistent terminology, a lower gear is an 'easier' gear, a higher gear a 'harder' gear. At the front a bigger cog is higher/'harder' at the rear a larger cog is lower'easier.

Parktool not only do good tools, they also tell you how to do 'stuff' on the bike with easy step by step instructions with videos.
This one for the rear/right shifting
https://www.parktool.com/blog/repair-help/rear-derailleur-adjustment
This for front/left
https://www.parktool.com/blog/repair-help/front-derailleur-adjustment

You are almost certainly just needing to adjust cable tension, but walk through other steps to familiarise yourself and make sure nothing is obviously wrong. No tools are needed to do the cable tension.