Uneven knitting

Hello everyone
I’m knitting a cardigan for a toddler. Its quite plain mostly plain stockingette with a few rows of texture in a contrast yarn.

Pattern is "Hayfield Baby Chunky 4407 "

The texture is formed like a bobble, in that I have to make 3 stitches : ( k1 yfwd k1) on the knit row and them knit them together on the next purl row

Problem is that my resulting bobbles are irregular, lumpy and uneven; not at all like the picture in the pattern even though I am pretty certain I am knitting them correctly.

Can anyone pleas advise how I can improve my technique and outcome.

I’m using the suggested yarn and needles size but finding it pretty difficult to complete the stitches easily or smoothly as the resulting 3 stitches which have to be knitted together are difficult to work as they are tight on the needle .

Thanks in advance for any help and advice

Welcome to KnittingHelp!
Try to work the k1 yo k1 a little more loosely, especially the yo. If you tend to knit on the tips of the needles, remember to push each new stitch onto the barrel of the needle.
It can be difficult to purl 3tog at the best of times, but if the sts are overly tight it becomes a real struggle. Maybe practice on a swatch to see if you can find a better tension. If all else fails, the texture stitch may even out a bit when you wash or block the sweater.
Darling pattern.
http://www.wool4less.co.uk/Sirdar-Hayfield-Baby-Chunky-Pattern-4407_A18PQD.aspx

Thanks very much for the tips. It’s a very sweet pattern and I’d love to be able to complete it nicely as it’s for my darling granddaughter .Hopefully for Christmas .