Instructions:I hope not to double post, I could only find a similar post from 1 year ago, which now the link to the voucher is "broken"!
Either sign up to the newsletter at the link provided, or print direct from here:
£10 off colour services over £30
£5 off your next Cut, Blowdry & Treatment
Vouchers valid from Sunday to Thursday now until 6th April and again from 19th April until 30th April
Terms and Condition are displayed on the voucher
I hope this helps somebody!