Have just checked symptoms for scarlet fever and the only one ds hasn't got is the red tongue -

[Dumplings]

He has a whitish coating on it instead!

Gp tomorrow?

he has had, in the past 3 days,

fever
head ache
tummy ache (without nausea)
sore thoat
snotty nose
pink sandpapery rash

Is this enough to take him to the docs with?

it's definately enough to take him to the doc with but I would also phone NHS direct tonight if I were you. Scarlet fever can be incredibly contagious and can be serious in the UK as its not a disease we see very often so we don't have high natural resistance (afaik, we had an outbreak at work recently). As far as I am aware outbreaks also have to be reported to the disease control people.
Mind you this sounds a lot like the bug that seems to be going round every man, woman and child I know at the moment and that definatley isn't scarlet fever.

The white coating comes off to reveal the red strawberry tongue. My boys had it earlier this year. Get Ds to a doc pronto because he'll need antibiotics to shake it off.

From the symptoms you've listed it definitely sounds like scarlet fever, especially if he has pussey tonsils. The sandpapery rash is the classic symptom though.

My oldest son had scarlet fever last automn. Our gp said that the strawberry tongue was the sign to look out for. You cant miss it, it really looks exactly like a strawberry. He had over 40 in fever, sore throat, was vomiting, headaches and light sensitivity. The only antibiotic that works for it, is Penicillin V.

Although it may not be scarlet fever, you son still sound pretty miserable, so worth checking out.