I think you have to do both, or soon will, if the lead is removable.

'Portable' applies to the equipment being tested...

i.e a permanent installation with a power lead straight from a distribution point (MCB, fused spur etc) doesn't need testing. Anything with a plug on does as it could be moved and could damage the lead making it unsafe.

There are guidelines as to when to test all different types of equipment, basically PC's once a year, fridges every 3 years, hand tools every 3-6 months.

Here is the IET info sheet on PAT.

http://www.theiet.org/factfiles/health/hsb34c.cfm?type=pdf

Note that it is up to 'the management' of the firm to apply a suitable scheme for PAT checks, there's no legislative requirements on timeframe other than a 'it should be checked every x' where 'x' is suitable for the equipment's use.

You can contact the IET for help in that respect, contact details at end of their info sheet.

Also the HSE advice on this area is here.

Maintaining electrical equipment safety

We do ours in house having had two guys go on a course paid for by a grant as far as I know, most cost effective in our opinion.

HTH.