Heathrow to Gatwick transfer

[MioDioMio]

Looking for a bit of advice as I usually use a regional airport but for various reasons I’ve booked a trip that takes me via Heathrow then my next flight is from Gatwick.
There is 5 hours between flights. Looking at the website for Heathrow it looks like there are various ways for transferring between the airports.
How would more experienced travellers from the SE recommend getting from Heathrow to Gatwick and are there any pitfalls to avoid?
Thank you

I would think the national express shuttle bus would be the most reliable and direct

I would take the National Express bus between them.

What time of day are the flights? National express are usually the best bet

Thank you. How much time do you think I need to allow myself to get out of Heathrow and to the bus? I’d only have hand luggage so I wouldn’t have to wait for
cases.

I land at 9am at Heathrow. Plane from Gatwick depart at 2pm

If you're on time and all goes well, you can be through pretty quickly if hand baggage only and if your domestic/can use the E gates.

Do you have to commit to a specific coach time? What are the options?

There looks to be four coaches an hour, which is great. Journey time of 1 hour 15 mins. Looks like you have to book a specific time, which is annoying.

First choice would be the coach or if there are any M25 issues you can get the Elizabeth Line to St Pancras and then Thameslink to Gatwick.

Further investigation on National Express website has uncovered I can by a flexible ticket (for more dollar, obvs) which would give me peace of mind.
Thank you all for your help.

You can book a flexi ticket and then change the time if needed!

Oh snap! 😂

Coach is your best bet

You can also book the coach online as soon as you are through passport control and know what the next one is. I've booked it literally standing next to the coach before. Or you can go with the flex ticket - your call.

Just bear in mind, if you land at 9am it may take an hour to get through baggage, passport control (if international) etc., and you may need to be a Gatwick 2 hours before the flight departure time.

This is my worry. I’ll only have hand luggage and it’s a domestic flight from Manchester so no passport checks?

Yes, hand luggage only and domestic is as quick as you can be.

Oh in that case I think you'll be fine! 👍

Thank you all, you’ve been been so helpful.