IT depends what your turnover is. For your size setup you need a merchant services agreement and a terminal machine.
I'm on my 5th agreement so I've tried lots of providers. The fastest payers are direct with elavon. You usually get the money next day. Other providers will quote 3 days but be careful some providers will count 3 days waiting plus the day you took the payment plus the day they make the payment plus the weekend - so you wait a week.
Some providers retain a minimum sum. It's often £1500. I once had an agreement were they held £1500 and paid a week late!
I am now with a very small company where I save a lot of money because you get a personal to you service. A chap came to visit me and asked to see my merchant service provider bills to see if he could save me money. He had a look and then told me that I was paying extra to accept contactless payments. I thought that because most of my transactions were over £30 it wasn't an issue - I was surprised when he showed me what it was costing me.
He asked to look at my machine and asked me about my wifi and mobile phone reception and whether I ever take my machine off site. Turned out I was paying £6 a month for a facility I don't need (off site use) and putting up with service connectivity issues when a cheaper machine would give me hassle free service!
I asked about the cost of compliance certification which I pay £5 a month for - and it was free.
He ended up giving me a quote which shaved a fraction of a percentage point off my existing deal - in return for waiting 3 days longer for my money in my bank account. This will save me a startling amount of money over the year.
The real savings will be much greater as he's given me information to help me manage my costs. They work on a referral basis, so pm me if you would like their contact info. There's no harm in having someone look at your bills and see if they can offer you a better deal is there?