I've finally cracked it my customer who lives in a rural location has a  a load of 95 amps now I've done the calculations properly I'm happy thats the max. In normal times it will be considerably less than this I didn't realise this to start with as I had incomplete information so in short a 100 amp single phase is adequate  I've told him if he adds more equipment he will need to ask his DNO  but until then all ok. Thankyou again for all your help  

That is PROBABLY fine, but a lot depends on how exactly the 95 amp figure was obtained.

If it was measured at 95 amps, then I might be a bit doubtful. It would only take one portable heater to produce a slight overload, two heaters and a tumble dryer to produce a significant overload.

If the 95 amps was the maximum recorded by a data logger over a reasonable time, then it depends. A typical loading of say 60 amps and a brief peak of 95 amps will almost certainly  be fine. If the load was at 95 amps for hours at a time then that is a bit worrying as even a small long term increase could end badly.

If the 95 amps was calculated by simple addition of appliance ratings, then almost certainly fine as the actual load will almost certainly be a lot less.

If the 95 amps was calculated in the usual way after diversity, then probably OK unless unusually intensive use of large loading appliances. is expected.

There is a huge difference between an electric shower that uses 40 amps for a few minutes and an industrial machine that uses 40 amps for hours at a time.

Kelly you wont get more than 100A single phase from SSE,(down here in Dorset) although as you live in Weymouth your customer might be (over the border(just the other side of Askers hill)) in WPD area. you would need to ask for a 2ϕ of 3ϕ supply or a 3ϕ supply.

The 95 amps was obtained by logging over a 3 day  period during his busiest time  so I'm confident that it never or rarely exceeds that figure. Also he's now told me he's moving his business  to a workshop with 3 phase I only found this out last nite