The average daily motion of the planets are:
Moon 13 degrees 11 minutes - at it's fatest it peeks around 15 degrees
Mercury 59 minutes *
Venus 59 minutes *
Sun 59 minutes
Mars 31 minutes *
Jupiter 5 minutes *
Saturn 2 minutes *
The outers move at less than 1 minute per day
However the average disguises the real situation day by day as all the starred planets and the outers have periods of retrograde motion, as well as direct. That being said, Mercury, the fastest moviing of them reaches a speed of up to 1 degree 40 minutes.
So the planets positions when you were born (apart for the Moon) will be very little different from the positions given at midnight in an ephemeris or on astro,com.
With no known birth time the conventional solutions are to cast a chart for any of the following:
Sunrise
True Noon (Sun's culmination)
Sunset
However the main choice seems to be the Sunrise chart, even though the Noon chart minimises the average error on the Moon's position - it will be no more than 7.5 degrees from your true birth time.
The real problem is that mentioned by ihcoyc. The planetary positions are relatively easy to determine with little error, your Ascendant and houses are much more difficult, as the Ascendant moves at an average of 1 degree every 4 minutes (time), so every 2 hours on average it will change sign.
As you were born in England, your birth time has not been publicly recorded (I know you know that but it will save someone telling you to look at your birth certificate LOL). So your best start is with your relatives. Can they remember approximately - even if it's only approximate enough to choose between Sunrise, Noon and Sunset charts. A skilled Astrologer can help you determine a time which fits well with the main events in your life but this is time consuming and usually you would have to pay for it - and it will not be objectively correct - merely a better stab than pot luck or a rough estimate from a relative.
The 'closeness' may well be significant, depending on how close they are - but as I don't know which planets they are and which houses they are really in, I can't help you any further. You can check with an introductory book and that may help but I'm not a fan of cookbook meanings of aspects as they ignore the house placements and for me those are more important than the aspect alone.
Good luck in getting some info on your birth time. If you end up with nothing then go for the Noon chart but remember to treat it as a tentative version