Fuel problem?

My 96 300tdi was fine yesterday. When I started it this morning to take son to football it was OK, maybe a bit lumpy but normal power for a couple of miles then suddenly on way back, little or no power. I had to come down the gears till I could only go along in second, then down to 1st. It would pick up very slightly every now and again but then lose all power. When in first, it would go along at 10 mph so have got her home. It is quite a cold morning but am doubting freezing diesel as it happened when engine was warm and not from start up? I am using same diesel as for previous 200 miles.
1 hour layer - I have just taken her out round the block and it is fine????
Any ideas please???

id check pipes from tank including pick up ,filter and lift pump,lift pump is a common failing ,diesel could freeze with a hot engine in pipes near the tank but i wouldnt have thought thats the case at all,undo front banjo on injection pump and bleed there after you worked on the system bleed till no air come out if you cant get rid of the air lift pump is sucking air in either through itself or pipe work etc ,if you cant find any problems try undoing filler cap next time it stalls

Could be the gauze filter blocking on the pick up pipe in the tank, this would unblock when the pump stops sucking.

Try blowing down the feed pipe to tank next time see if it clears it

Help! My 1996 300 tdi defender has developed a severe lack of power. It is Ok for the first few hundred yards then gradually to nearly nothing. Going up hill means down the grears to about 3 MPH. Occasionally it is too much for 1st so I have to stop, wait for a while then carry on. It feels like fuel starvation so have checked fuel line. The sedimenter has previously been removed so fuel line (which looks quite new) goes straight up front. It is a fairly new filter and I have just fitted a new pump. Exactly the same. When revving (which it does from idle) the smoke (initially black) then goes a whitish colour (unburnt fuel ?????) When revved, both the top air pipe and the short right angle air pipe to turbo go very hard so turbo is building up pressure and whistles as usual. When returning to idle it is very lumpy for a few seconds (as if diesel levels are building up again?) The valve on the manifold (EGR?) has been blanked off. I had the same symptoms about 3 weeks ago but it just cured itself?????
Where now?