Black and white film NEEDS to be self-processed! The key to good b&w is having total control over the whole process - from exposure to print. My advice would be:
1. Use Delta 100 - very forgiving film
2. Rate it at 100 ASA and use zone-system for exposure control. Simplified - Basically meter the darkest area you want to see full detail - in the example you show this would probably be the shadow areas under the arches on the bridge. Next meter the highlight area where you want to see full detail - try a white cloud (above background hills to the left of your example). Measure the range between these two readings: 5 stops difference will require Normal development. If the range is less than 5 stops then development will need to be increased (up to a max of 2 stops usually), if the range is greater than 5 stops then the development time will need to be decreased(usually by a max of minus 2 stops).
3. Once you've determined the development you can concentrate on the exposure for the negative
4. Meter the important shadow area (again) - under the arches. The reading you get will be Zone 5 or 18% grey. You then decrease exposure by 2 stops to move the measurement to Zone 3 (IMPORTANT SHADOW AREA). Do this by either adjusting the shutter speed or ASA setting. The adjusted reading you get now is the exposure for the scene.
5. If you use filters then you will need to include the filter factor into the calculation

I would do this at the ASA setting stage and use one filter to leave the setting constant - I agree with Jo, a red is not suitable for this scene - in fact, not much use for anything
6. Try a yellow filter - or at most a light orange ... plenty for UK landscapes. With a yellow/light orange I would rate Delta 100 at about 64ASA as a start.
This may sound complicated but in practice`its not! Just plug the film speed/filter factor settings into your meter and work methodically!
7. Once film is exposed mark holder with the DEVELOPMENT, either N for Normal, N- if a decrease is required and N+ if you need to increase dev time.
8. Get yourself a CombiPlan Tank or use trays if you have a darkroom. With Delta 100 try using a bog-standard dev like Paterson FX-39. Normal development time is in the region of 10 minutes, for plus or minus development try increasing and decreasing dev time for about 15% per stop e.g. N-2 would require a decrease in time of 30%, N+2 an increase of 30% - experimentation/testing is required but once you find the correct combination for you it works every time!
A recap
1. ASA setting in meter of 64ASA (to allow for filter).
2. Meter zonal (contrast) range to calculate DEvelopment time, either N, N-1 etc. (High contrast = N- dev, low contrast = N+ dev).
3. Measure Zone 3 (important shadow area) in scene and decrease reading by 2 stops.
4. Expose at this setting.
5. mark film holder with DEV time.
6. Cross your fingers and hope for the best
