My nephew will be attending Luton University in May, & I am assisting him with his move.

We will be traveling separately from the States & arriving on different days.

I will have three pieces of luggage...two 62 linear inch (weighing 30 kg) & one 45 linear inch (weighing 20 kg). Also, one handbag.

I plan to use the National Express bus from LHR to LTN. I don't want to use the Tube for part of the way because I cannot handle that much luggage efficiently by myself under the conditions that the Tube poses. Also, I do not want to risk injuring another person nor myself. I remember how steep the escalators are.

My question is: Is that amount of luggage acceptable on National Express, or should I plan on making two trips to Luton from Heathrow?
The latter is do-able, as I can use the airport luggage storage if I must make a second trip.

Or do I have any other option besides National Express?

P.S. If I do need to use National Express for two trips, I plan to use the Thameslink & Tube on the return to LHR, as I will not be luggage-laden.