From Tax side of things....
You will both have to register as Self Employed, pay �10 a month in respect of Class 2 National Insurance, then fill in your tax returns to advise of your share of profits each year. You will pay 20% tax on all your profits above �5435, and 8% Class 4 National Insurance on everything above �5435 too.
If you believe your turnover (not profit) will rise to over �64k per year, you should think of becoming VAT registered. So will add 17.5% to your invoices to clients.
As for business side of things, I have a lot of espereicen as kennelamid, but you also seem to , so this will not be an issue. I'd get good insurance in case of disease amongst animals etc.