Cascade DK, hook size and pattern help

[Cloudberry]

For some very weird reason MN asked me to log in again the other day and has resurrected a user name I used years ago and has rejected the one I have been using - rubbishisthebest. Anyway my next project is wristwarmers for my 7 year old niece. Only pattern I've found is in Crochet - the complete step by step guide published by DK in case anyone knows it. I bought some Cascade Superpaint wool from Woolwarehouse which says it's a DK yarn. My pattern says DK yarn and 4 hook and chain 21. Well to make up the wristwarmers you just stitch up the seam and having done about 7 rows, there is no way it will fit a 7 year old let alone an 8-10 year old which is what the pattern suggests.

What should I do - up the hook size ( have done a few rows with a 4.5 hook which has made some difference)? Increase the foundation chains? Any suggestions very much appreciated.

Looking on Woolwarehouse, the recommended hook size is 4 or 4.5mm so going up to a 4.5 isn't unlikely. I wouldn't go up further really as it can make the fabric more "holey". I'd try increasing the foundation chains if hook size alone doesn't help.

Is there a gauge given for the pattern? I rarely bother with crocheting a swatch to check tension and gauge but it might be worthwhile.

Soupdragon, thank you. Tension given is 14 sts x 16 rows per 10 cm (4in). I've never made anything that requires this so I feel rather confused about how to do this especially as I don't have a tape measure or ruler here in hospital, though I suppose I could ask the nurses if they have anything. I've done a swatch with the 4 mm hook, dc though next thing is I eyed to work out how many rows I've really done .......

I reckon I've done about 15 rows, 21 stitches.