Must they be both in the same episode? I can think of a few episodes with each in them at least separately.
Tailor:
Spring Fever - Compo gets fitted for a suit to impress a new housekeeper arriving by bus.
An episode where they try to find Compo work and offer the tailor him as a 'Before Sample' to entice others to buy. I think Auntie has an employment office and Smiler is displayed in the window in stocks.
Another where a tailor is in his shop window and the guys yell something to him from the street. The guys threaten to disclose some info on the tailor who panics then lets them inside. Possibly the guys lady friend whose eyes are the same color as his favorite fabric.
Another with Trevor Bannister as the tailor. That may be the one that Dick mentioned - yep, Who's Got Rythm
Green grocer:
Dancing Feet - Episode that has a possible for Open All Hours scene where the guys go into a grocers for something - think to get Compo some medicine. They find Nora and Ivy in there shopping. The ladies are poking and prodding the produce. The shop keeper shows the guys a small shelf with small selection of bottles on it.
Greenfingers - Where they try to show up a grocer by wheeling a huge carrot past his house. Think Clegg was talking of finding better veggies then he is getting at his current place.
Okay the answer was "Have you got a light mate" the actor David Williams appeared as the greengrocer, he was also Fairburn the C0-op tailor in Getting Sam home, he also appeared in 3 other episodes