Vat registration is quite simple

Non Vat Registered:
You buy an item for £10+vat - you pay £11.75
You sell an item for £100 - you make £88.25
You Buy diagnosis equipment of £30+vat = £34.25

Total Profit = £100 - £34.25 - £11.75 = £54

Vat Registered:
You buy an item for £10+vat - you pay £11.75
You sell an Item for £100 - You pay vat of £14.89
You Buy diagnosis equipment of £30+vat = £34.25
Vat you pay to the taxman: £14.89 - £1.75 - £4.25 = £8.89

£100 - 30 - 10 - 8.89 = £48.89

You will be slightly worse off - however it is something any growing business has to take into account - unless you sell b2b like we do, in which case you simple write +vat on all of the quotes lol